See tutors' answers!

Algebra ->  Tutoring on algebra.com -> See tutors' answers!      Log On


   
By Tutor
 | By Problem Number | 

Tutor:
New! Get regular updates about newly solved problems via algebra.com's RSS system.

Recent problems solved by 'jim_thompson5910'

jim_thompson5910 answered: 28703 problems
Jump to solutions: 0..29 , 30..59 , 60..89 , 90..119 , 120..149 , 150..179 , 180..209 , 210..239 , 240..269 , 270..299 , 300..329 , 330..359 , 360..389 , 390..419 , 420..449 , 450..479 , 480..509 , 510..539 , 540..569 , 570..599 , 600..629 , 630..659 , 660..689 , 690..719 , 720..749 , 750..779 , 780..809 , 810..839 , 840..869 , 870..899 , 900..929 , 930..959 , 960..989 , 990..1019 , 1020..1049 , 1050..1079 , 1080..1109 , 1110..1139 , 1140..1169 , 1170..1199 , 1200..1229 , 1230..1259 , 1260..1289 , 1290..1319 , 1320..1349 , 1350..1379 , 1380..1409 , 1410..1439 , 1440..1469 , 1470..1499 , 1500..1529 , 1530..1559 , 1560..1589 , 1590..1619 , 1620..1649 , 1650..1679 , 1680..1709 , 1710..1739 , 1740..1769 , 1770..1799 , 1800..1829 , 1830..1859 , 1860..1889 , 1890..1919 , 1920..1949 , 1950..1979 , 1980..2009 , 2010..2039 , 2040..2069 , 2070..2099 , 2100..2129 , 2130..2159 , 2160..2189 , 2190..2219 , 2220..2249 , 2250..2279 , 2280..2309 , 2310..2339 , 2340..2369 , 2370..2399 , 2400..2429 , 2430..2459 , 2460..2489 , 2490..2519 , 2520..2549 , 2550..2579 , 2580..2609 , 2610..2639 , 2640..2669 , 2670..2699 , 2700..2729 , 2730..2759 , 2760..2789 , 2790..2819 , 2820..2849 , 2850..2879 , 2880..2909 , 2910..2939 , 2940..2969 , 2970..2999 , 3000..3029 , 3030..3059 , 3060..3089 , 3090..3119 , 3120..3149 , 3150..3179 , 3180..3209 , 3210..3239 , 3240..3269 , 3270..3299 , 3300..3329 , 3330..3359 , 3360..3389 , 3390..3419 , 3420..3449 , 3450..3479 , 3480..3509 , 3510..3539 , 3540..3569 , 3570..3599 , 3600..3629 , 3630..3659 , 3660..3689 , 3690..3719 , 3720..3749 , 3750..3779 , 3780..3809 , 3810..3839 , 3840..3869 , 3870..3899 , 3900..3929 , 3930..3959 , 3960..3989 , 3990..4019 , 4020..4049 , 4050..4079 , 4080..4109 , 4110..4139 , 4140..4169 , 4170..4199 , 4200..4229 , 4230..4259 , 4260..4289 , 4290..4319 , 4320..4349 , 4350..4379 , 4380..4409 , 4410..4439 , 4440..4469 , 4470..4499 , 4500..4529 , 4530..4559 , 4560..4589 , 4590..4619 , 4620..4649 , 4650..4679 , 4680..4709 , 4710..4739 , 4740..4769 , 4770..4799 , 4800..4829 , 4830..4859 , 4860..4889 , 4890..4919 , 4920..4949 , 4950..4979 , 4980..5009 , 5010..5039 , 5040..5069 , 5070..5099 , 5100..5129 , 5130..5159 , 5160..5189 , 5190..5219 , 5220..5249 , 5250..5279 , 5280..5309 , 5310..5339 , 5340..5369 , 5370..5399 , 5400..5429 , 5430..5459 , 5460..5489 , 5490..5519 , 5520..5549 , 5550..5579 , 5580..5609 , 5610..5639 , 5640..5669 , 5670..5699 , 5700..5729 , 5730..5759 , 5760..5789 , 5790..5819 , 5820..5849 , 5850..5879 , 5880..5909 , 5910..5939 , 5940..5969 , 5970..5999 , 6000..6029 , 6030..6059 , 6060..6089 , 6090..6119 , 6120..6149 , 6150..6179 , 6180..6209 , 6210..6239 , 6240..6269 , 6270..6299 , 6300..6329 , 6330..6359 , 6360..6389 , 6390..6419 , 6420..6449 , 6450..6479 , 6480..6509 , 6510..6539 , 6540..6569 , 6570..6599 , 6600..6629 , 6630..6659 , 6660..6689 , 6690..6719 , 6720..6749 , 6750..6779 , 6780..6809 , 6810..6839 , 6840..6869 , 6870..6899 , 6900..6929 , 6930..6959 , 6960..6989 , 6990..7019 , 7020..7049 , 7050..7079 , 7080..7109 , 7110..7139 , 7140..7169 , 7170..7199 , 7200..7229 , 7230..7259 , 7260..7289 , 7290..7319 , 7320..7349 , 7350..7379 , 7380..7409 , 7410..7439 , 7440..7469 , 7470..7499 , 7500..7529 , 7530..7559 , 7560..7589 , 7590..7619 , 7620..7649 , 7650..7679 , 7680..7709 , 7710..7739 , 7740..7769 , 7770..7799 , 7800..7829 , 7830..7859 , 7860..7889 , 7890..7919 , 7920..7949 , 7950..7979 , 7980..8009 , 8010..8039 , 8040..8069 , 8070..8099 , 8100..8129 , 8130..8159 , 8160..8189 , 8190..8219 , 8220..8249 , 8250..8279 , 8280..8309 , 8310..8339 , 8340..8369 , 8370..8399 , 8400..8429 , 8430..8459 , 8460..8489 , 8490..8519 , 8520..8549 , 8550..8579 , 8580..8609 , 8610..8639 , 8640..8669 , 8670..8699 , 8700..8729 , 8730..8759 , 8760..8789 , 8790..8819 , 8820..8849 , 8850..8879 , 8880..8909 , 8910..8939 , 8940..8969 , 8970..8999 , 9000..9029 , 9030..9059 , 9060..9089 , 9090..9119 , 9120..9149 , 9150..9179 , 9180..9209 , 9210..9239 , 9240..9269 , 9270..9299 , 9300..9329 , 9330..9359 , 9360..9389 , 9390..9419 , 9420..9449 , 9450..9479 , 9480..9509 , 9510..9539 , 9540..9569 , 9570..9599 , 9600..9629 , 9630..9659 , 9660..9689 , 9690..9719 , 9720..9749 , 9750..9779 , 9780..9809 , 9810..9839 , 9840..9869 , 9870..9899 , 9900..9929 , 9930..9959 , 9960..9989 , 9990..10019 , 10020..10049 , 10050..10079 , 10080..10109 , 10110..10139 , 10140..10169 , 10170..10199 , 10200..10229 , 10230..10259 , 10260..10289 , 10290..10319 , 10320..10349 , 10350..10379 , 10380..10409 , 10410..10439 , 10440..10469 , 10470..10499 , 10500..10529 , 10530..10559 , 10560..10589 , 10590..10619 , 10620..10649 , 10650..10679 , 10680..10709 , 10710..10739 , 10740..10769 , 10770..10799 , 10800..10829 , 10830..10859 , 10860..10889 , 10890..10919 , 10920..10949 , 10950..10979 , 10980..11009 , 11010..11039 , 11040..11069 , 11070..11099 , 11100..11129 , 11130..11159 , 11160..11189 , 11190..11219 , 11220..11249 , 11250..11279 , 11280..11309 , 11310..11339 , 11340..11369 , 11370..11399 , 11400..11429 , 11430..11459 , 11460..11489 , 11490..11519 , 11520..11549 , 11550..11579 , 11580..11609 , 11610..11639 , 11640..11669 , 11670..11699 , 11700..11729 , 11730..11759 , 11760..11789 , 11790..11819 , 11820..11849 , 11850..11879 , 11880..11909 , 11910..11939 , 11940..11969 , 11970..11999 , 12000..12029 , 12030..12059 , 12060..12089 , 12090..12119 , 12120..12149 , 12150..12179 , 12180..12209 , 12210..12239 , 12240..12269 , 12270..12299 , 12300..12329 , 12330..12359 , 12360..12389 , 12390..12419 , 12420..12449 , 12450..12479 , 12480..12509 , 12510..12539 , 12540..12569 , 12570..12599 , 12600..12629 , 12630..12659 , 12660..12689 , 12690..12719 , 12720..12749 , 12750..12779 , 12780..12809 , 12810..12839 , 12840..12869 , 12870..12899 , 12900..12929 , 12930..12959 , 12960..12989 , 12990..13019 , 13020..13049 , 13050..13079 , 13080..13109 , 13110..13139 , 13140..13169 , 13170..13199 , 13200..13229 , 13230..13259 , 13260..13289 , 13290..13319 , 13320..13349 , 13350..13379 , 13380..13409 , 13410..13439 , 13440..13469 , 13470..13499 , 13500..13529 , 13530..13559 , 13560..13589 , 13590..13619 , 13620..13649 , 13650..13679 , 13680..13709 , 13710..13739 , 13740..13769 , 13770..13799 , 13800..13829 , 13830..13859 , 13860..13889 , 13890..13919 , 13920..13949 , 13950..13979 , 13980..14009 , 14010..14039 , 14040..14069 , 14070..14099 , 14100..14129 , 14130..14159 , 14160..14189 , 14190..14219 , 14220..14249 , 14250..14279 , 14280..14309 , 14310..14339 , 14340..14369 , 14370..14399 , 14400..14429 , 14430..14459 , 14460..14489 , 14490..14519 , 14520..14549 , 14550..14579 , 14580..14609 , 14610..14639 , 14640..14669 , 14670..14699 , 14700..14729 , 14730..14759 , 14760..14789 , 14790..14819 , 14820..14849 , 14850..14879 , 14880..14909 , 14910..14939 , 14940..14969 , 14970..14999 , 15000..15029 , 15030..15059 , 15060..15089 , 15090..15119 , 15120..15149 , 15150..15179 , 15180..15209 , 15210..15239 , 15240..15269 , 15270..15299 , 15300..15329 , 15330..15359 , 15360..15389 , 15390..15419 , 15420..15449 , 15450..15479 , 15480..15509 , 15510..15539 , 15540..15569 , 15570..15599 , 15600..15629 , 15630..15659 , 15660..15689 , 15690..15719 , 15720..15749 , 15750..15779 , 15780..15809 , 15810..15839 , 15840..15869 , 15870..15899 , 15900..15929 , 15930..15959 , 15960..15989 , 15990..16019 , 16020..16049 , 16050..16079 , 16080..16109 , 16110..16139 , 16140..16169 , 16170..16199 , 16200..16229 , 16230..16259 , 16260..16289 , 16290..16319 , 16320..16349 , 16350..16379 , 16380..16409 , 16410..16439 , 16440..16469 , 16470..16499 , 16500..16529 , 16530..16559 , 16560..16589 , 16590..16619 , 16620..16649 , 16650..16679 , 16680..16709 , 16710..16739 , 16740..16769 , 16770..16799 , 16800..16829 , 16830..16859 , 16860..16889 , 16890..16919 , 16920..16949 , 16950..16979 , 16980..17009 , 17010..17039 , 17040..17069 , 17070..17099 , 17100..17129 , 17130..17159 , 17160..17189 , 17190..17219 , 17220..17249 , 17250..17279 , 17280..17309 , 17310..17339 , 17340..17369 , 17370..17399 , 17400..17429 , 17430..17459 , 17460..17489 , 17490..17519 , 17520..17549 , 17550..17579 , 17580..17609 , 17610..17639 , 17640..17669 , 17670..17699 , 17700..17729 , 17730..17759 , 17760..17789 , 17790..17819 , 17820..17849 , 17850..17879 , 17880..17909 , 17910..17939 , 17940..17969 , 17970..17999 , 18000..18029 , 18030..18059 , 18060..18089 , 18090..18119 , 18120..18149 , 18150..18179 , 18180..18209 , 18210..18239 , 18240..18269 , 18270..18299 , 18300..18329 , 18330..18359 , 18360..18389 , 18390..18419 , 18420..18449 , 18450..18479 , 18480..18509 , 18510..18539 , 18540..18569 , 18570..18599 , 18600..18629 , 18630..18659 , 18660..18689 , 18690..18719 , 18720..18749 , 18750..18779 , 18780..18809 , 18810..18839 , 18840..18869 , 18870..18899 , 18900..18929 , 18930..18959 , 18960..18989 , 18990..19019 , 19020..19049 , 19050..19079 , 19080..19109 , 19110..19139 , 19140..19169 , 19170..19199 , 19200..19229 , 19230..19259 , 19260..19289 , 19290..19319 , 19320..19349 , 19350..19379 , 19380..19409 , 19410..19439 , 19440..19469 , 19470..19499 , 19500..19529 , 19530..19559 , 19560..19589 , 19590..19619 , 19620..19649 , 19650..19679 , 19680..19709 , 19710..19739 , 19740..19769 , 19770..19799 , 19800..19829 , 19830..19859 , 19860..19889 , 19890..19919 , 19920..19949 , 19950..19979 , 19980..20009 , 20010..20039 , 20040..20069 , 20070..20099 , 20100..20129 , 20130..20159 , 20160..20189 , 20190..20219 , 20220..20249 , 20250..20279 , 20280..20309 , 20310..20339 , 20340..20369 , 20370..20399 , 20400..20429 , 20430..20459 , 20460..20489 , 20490..20519 , 20520..20549 , 20550..20579 , 20580..20609 , 20610..20639 , 20640..20669 , 20670..20699 , 20700..20729 , 20730..20759 , 20760..20789 , 20790..20819 , 20820..20849 , 20850..20879 , 20880..20909 , 20910..20939 , 20940..20969 , 20970..20999 , 21000..21029 , 21030..21059 , 21060..21089 , 21090..21119 , 21120..21149 , 21150..21179 , 21180..21209 , 21210..21239 , 21240..21269 , 21270..21299 , 21300..21329 , 21330..21359 , 21360..21389 , 21390..21419 , 21420..21449 , 21450..21479 , 21480..21509 , 21510..21539 , 21540..21569 , 21570..21599 , 21600..21629 , 21630..21659 , 21660..21689 , 21690..21719 , 21720..21749 , 21750..21779 , 21780..21809 , 21810..21839 , 21840..21869 , 21870..21899 , 21900..21929 , 21930..21959 , 21960..21989 , 21990..22019 , 22020..22049 , 22050..22079 , 22080..22109 , 22110..22139 , 22140..22169 , 22170..22199 , 22200..22229 , 22230..22259 , 22260..22289 , 22290..22319 , 22320..22349 , 22350..22379 , 22380..22409 , 22410..22439 , 22440..22469 , 22470..22499 , 22500..22529 , 22530..22559 , 22560..22589 , 22590..22619 , 22620..22649 , 22650..22679 , 22680..22709 , 22710..22739 , 22740..22769 , 22770..22799 , 22800..22829 , 22830..22859 , 22860..22889 , 22890..22919 , 22920..22949 , 22950..22979 , 22980..23009 , 23010..23039 , 23040..23069 , 23070..23099 , 23100..23129 , 23130..23159 , 23160..23189 , 23190..23219 , 23220..23249 , 23250..23279 , 23280..23309 , 23310..23339 , 23340..23369 , 23370..23399 , 23400..23429 , 23430..23459 , 23460..23489 , 23490..23519 , 23520..23549 , 23550..23579 , 23580..23609 , 23610..23639 , 23640..23669 , 23670..23699 , 23700..23729 , 23730..23759 , 23760..23789 , 23790..23819 , 23820..23849 , 23850..23879 , 23880..23909 , 23910..23939 , 23940..23969 , 23970..23999 , 24000..24029 , 24030..24059 , 24060..24089 , 24090..24119 , 24120..24149 , 24150..24179 , 24180..24209 , 24210..24239 , 24240..24269 , 24270..24299 , 24300..24329 , 24330..24359 , 24360..24389 , 24390..24419 , 24420..24449 , 24450..24479 , 24480..24509 , 24510..24539 , 24540..24569 , 24570..24599 , 24600..24629 , 24630..24659 , 24660..24689 , 24690..24719 , 24720..24749 , 24750..24779 , 24780..24809 , 24810..24839 , 24840..24869 , 24870..24899 , 24900..24929 , 24930..24959 , 24960..24989 , 24990..25019 , 25020..25049 , 25050..25079 , 25080..25109 , 25110..25139 , 25140..25169 , 25170..25199 , 25200..25229 , 25230..25259 , 25260..25289 , 25290..25319 , 25320..25349 , 25350..25379 , 25380..25409 , 25410..25439 , 25440..25469 , 25470..25499 , 25500..25529 , 25530..25559 , 25560..25589 , 25590..25619 , 25620..25649 , 25650..25679 , 25680..25709 , 25710..25739 , 25740..25769 , 25770..25799 , 25800..25829 , 25830..25859 , 25860..25889 , 25890..25919 , 25920..25949 , 25950..25979 , 25980..26009 , 26010..26039 , 26040..26069 , 26070..26099 , 26100..26129 , 26130..26159 , 26160..26189 , 26190..26219 , 26220..26249 , 26250..26279 , 26280..26309 , 26310..26339 , 26340..26369 , 26370..26399 , 26400..26429 , 26430..26459 , 26460..26489 , 26490..26519 , 26520..26549 , 26550..26579 , 26580..26609 , 26610..26639 , 26640..26669 , 26670..26699 , 26700..26729 , 26730..26759 , 26760..26789 , 26790..26819 , 26820..26849 , 26850..26879 , 26880..26909 , 26910..26939 , 26940..26969 , 26970..26999 , 27000..27029 , 27030..27059 , 27060..27089 , 27090..27119 , 27120..27149 , 27150..27179 , 27180..27209 , 27210..27239 , 27240..27269 , 27270..27299 , 27300..27329 , 27330..27359 , 27360..27389 , 27390..27419 , 27420..27449 , 27450..27479 , 27480..27509 , 27510..27539 , 27540..27569 , 27570..27599 , 27600..27629 , 27630..27659 , 27660..27689 , 27690..27719 , 27720..27749 , 27750..27779 , 27780..27809 , 27810..27839 , 27840..27869 , 27870..27899 , 27900..27929 , 27930..27959 , 27960..27989 , 27990..28019 , 28020..28049 , 28050..28079 , 28080..28109 , 28110..28139 , 28140..28169 , 28170..28199 , 28200..28229 , 28230..28259 , 28260..28289 , 28290..28319 , 28320..28349 , 28350..28379 , 28380..28409 , 28410..28439 , 28440..28469 , 28470..28499 , 28500..28529 , 28530..28559 , 28560..28589 , 28590..28619 , 28620..28649 , 28650..28679 , 28680..28709, >>Next

Graphs/122217: If f (x) = 5x – 1, find the following:
9. f (a -2)

1 solutions

Answer 89710 by jim_thompson5910(28715) About Me  on 2008-01-23 23:28:11 (Show Source):
You can put this solution on YOUR website!
Let's evaluate f%28a-2%29


f%28x%29=5x-1 Start with the given function.


f%28a-2%29=5%28a-2%29-1 Plug in x=a-2. In other words, replace each x with a-2.


f%28a-2%29=5a-10-1 Distribute


f%28a-2%29=5a-11 Combine like terms


Graphs/122216: If f (x) = 4x -3, find the following:
8. f (-1)

1 solutions

Answer 89709 by jim_thompson5910(28715) About Me  on 2008-01-23 23:25:26 (Show Source):
You can put this solution on YOUR website!

Let's evaluate f%28-1%29


f%28x%29=4x-3 Start with the given function.


f%28-1%29=4%28-1%29-3 Plug in x=-1. In other words, replace each x with -1.


f%28-1%29=-4-3 Multiply 4 and -1 to get -4


f%28-1%29=-7 Now combine like terms


Graphs/122215: Graph the function for each.
7. f (x) = -2x – 5


1 solutions

Answer 89708 by jim_thompson5910(28715) About Me  on 2008-01-23 23:23:59 (Show Source):
You can put this solution on YOUR website!

Looking at y=-2x-5 we can see that the equation is in slope-intercept form y=mx%2Bb where the slope is m=-2 and the y-intercept is b=-5


Since b=-5 this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis

So we have one point




Now since the slope is comprised of the "rise" over the "run" this means
slope=rise%2Frun

Also, because the slope is -2, this means:

rise%2Frun=-2%2F1


which shows us that the rise is -2 and the run is 1. This means that to go from point to point, we can go down 2 and over 1



So starting at , go down 2 units


and to the right 1 unit to get to the next point



Now draw a line through these points to graph y=-2x-5

So this is the graph of y=-2x-5 through the points and


Graphs/122214: Rewrite each equation as a function of x.
6. -3x + 4y = 11

1 solutions

Answer 89707 by jim_thompson5910(28715) About Me  on 2008-01-23 23:22:05 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Converting Linear Equations in Standard form to Slope-Intercept Form (and vice versa)


-3%2Ax%2B4%2Ay=11Start with the given equation



4%2Ay=11%2B3%2Ax Add 3%2Ax to both sides

y=%281%2F4%29%2811%2B3%2Ax%29 Multiply both sides by 1%2F4

y=%281%2F4%29%2811%29-%281%2F4%29%28-3%29x%29 Distribute 1%2F4

y=11%2F4%2B%283%2F4%29x Multiply

y=%283%2F4%29%2Ax%2B11%2F4 Rearrange the terms

y=%283%2F4%29%2Ax%2B11%2F4 Reduce any fractions

So the equation is now in slope-intercept form (y=mx%2Bb) where m=3%2F4 (the slope) and b=11%2F4 (the y-intercept)


Graphs/122213: Evaluate each function for the value specified.

5. f (x) = x2 - 7x + 10;
find (a) f (0), (b) f (5), and (c) f (-2).

1 solutions

Answer 89706 by jim_thompson5910(28715) About Me  on 2008-01-23 23:20:12 (Show Source):
You can put this solution on YOUR website!
a)


Let's evaluate f%280%29


f%28x%29=x%5E2-7x%2B10 Start with the given function.


f%280%29=%280%29%5E2-7%280%29%2B10 Plug in x=0. In other words, replace each x with 0.


f%280%29=%280%29-7%280%29%2B10 Evaluate %280%29%5E2 to get 0.


f%280%29=%280%29%2B0%2B10 Multiply -7 and 0 to get 0


f%280%29=10 Now combine like terms





b)


Let's evaluate f%285%29


f%28x%29=x%5E2-7x%2B10 Start with the given function.


f%285%29=%285%29%5E2-7%285%29%2B10 Plug in x=5. In other words, replace each x with 5.


f%285%29=%2825%29-7%285%29%2B10 Evaluate %285%29%5E2 to get 25.


f%285%29=%2825%29-35%2B10 Multiply -7 and 5 to get -35


f%285%29=0 Now combine like terms






c)


Let's evaluate f%28-2%29


f%28x%29=x%5E2-7x%2B10 Start with the given function.


f%28-2%29=%28-2%29%5E2-7%28-2%29%2B10 Plug in x=-2. In other words, replace each x with -2.


f%28-2%29=%284%29-7%28-2%29%2B10 Evaluate %28-2%29%5E2 to get 4.


f%28-2%29=%284%29%2B14%2B10 Multiply -7 and -2 to get 14


f%28-2%29=28 Now combine like terms


Graphs/122212: 4. Number problems. You have at least $30 in change in your drawer, consisting of dimes and quarters. Write an inequality that shows the different number of coins in your drawer.
1 solutions

Answer 89705 by jim_thompson5910(28715) About Me  on 2008-01-23 23:17:35 (Show Source):
You can put this solution on YOUR website!
Let d=# of dimes, q=# of quarters, s=sum of your money


Since a dime is 10 cents, it is $0.10 by conversion from cents to dollars. Also a quarter, which is 25 cents, is $0.25


So the sum of your money would be s=0.1d%2B0.25q

Since you have at least $30, this means that the sum of your money is greater than $30 like this:

s%3E30



0.1d%2B0.25q%3E30 Now plug in s=0.1d%2B0.25q



Answer:


So the inequality that represents this problem is


0.1d%2B0.25q%3E30


Graphs/122210: Graph each of the following inequalities.

3. 3x – 4y > 12

1 solutions

Answer 89703 by jim_thompson5910(28715) About Me  on 2008-01-23 23:09:13 (Show Source):
You can put this solution on YOUR website!
In order to graph 3x-4y%3E12, we need to graph the equation 3x-4y=12 (just replace the inequality sign with an equal sign).
So lets graph the line 3x-4y=12 (note: if you need help with graphing, check out this solver)
+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+%283%2F4%29x-3%29+ graph of 3x-4y=12
Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality 3x-4y%3E12 with the test point

Substitute (0,0) into the inequality
3%280%29-4%280%29%3E12 Plug in x=0 and y=0
0%3E12 Simplify



(note: for some reason, some of the following images do not display correctly in Internet Explorer. So I recommend the use of
Firefox to see these images.)


Since this inequality is not true, we do not shade the entire region that contains (0,0). So this means we shade the region that is on the opposite side of the line
Graph of 3x-4y%3E12 with the boundary (which is the line 3x-4y=12 in red) and the shaded region (in green)
(note: since the inequality contains a greater-than sign, this means the boundary is excluded. This means the solid red line is really a dashed line)


Graphs/122209: Graph each of the following inequalities.
2. 4x + y ≥ 4

1 solutions

Answer 89702 by jim_thompson5910(28715) About Me  on 2008-01-23 23:06:45 (Show Source):
You can put this solution on YOUR website!
In order to graph 4x%2By%3E=4, we need to graph the equation 4x%2By=4 (just replace the inequality sign with an equal sign).
So lets graph the line 4x%2By=4 (note: if you need help with graphing, check out this solver)
+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+-4x%2B4%29+ graph of 4x%2By=4
Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality 4x%2By%3E=4 with the test point

Substitute (0,0) into the inequality
4%280%29%2B%280%29%3E=4 Plug in x=0 and y=0
0%3E=4 Simplify



(note: for some reason, some of the following images do not display correctly in Internet Explorer. So I recommend the use of
Firefox to see these images.)


Since this inequality is not true, we do not shade the entire region that contains (0,0). So this means we shade the region that is on the opposite side of the line
Graph of 4x%2By%3E=4 with the boundary (which is the line 4x%2By=4 in red) and the shaded region (in green)


Graphs/122208: We have graphed the boundary line for the linear inequality. Determine the correct half – plane in each case, and complete the graph.

y>3
1 solutions

Answer 89701 by jim_thompson5910(28715) About Me  on 2008-01-23 23:03:41 (Show Source):
You can put this solution on YOUR website!
Start with the graph of y=3


+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+3%29+ graph of y=3


Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality y%3E3 with the test point

Substitute (0,0) into the inequality
%280%29%3E3 Plug in x=0 and y=0
0%3E3 Simplify



(note: for some reason, some of the following images do not display correctly in Internet Explorer. So I recommend the use of Firefox to see these images.)


Since this inequality is not true, we do not shade the entire region that contains (0,0). So this means we shade the region that is on the opposite side of the line
Graph of y%3E3 with the boundary (which is the line y=3 in red) and the shaded region (in green)
(note: since the inequality contains a greater-than sign, this means the boundary is excluded. This means the solid red line is really a dashed line)



So the correct half-plane is above the line y=3


Graphs/122153: I am stuck on this linear equation. I also need to find the rise over run too. This is what I have so far.

2x + 4y + 1 = 0
4y = 2x - 1
/4 /4 /4
y = 2/4x -1/4
y = 1/2x -1/4

1 solutions

Answer 89673 by jim_thompson5910(28715) About Me  on 2008-01-23 19:48:28 (Show Source):
You can put this solution on YOUR website!
You made a mistake in converting to slope-intercept form

"4y = 2x - 1" <--- In this step, it should be -2x since you subtract 2x from both sides


So the equation in slope-intercept form is


y+=+-%281%2F2%29x+-1%2F4





Looking at y=-%281%2F2%29x-1%2F4 we can see that the equation is in slope-intercept form y=mx%2Bb where the slope is m=-1%2F2 and the y-intercept is b=-1%2F4


Since b=-1%2F4 this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis

So we have one point




Now since the slope is comprised of the "rise" over the "run" this means
slope=rise%2Frun

Also, because the slope is -1%2F2, this means:

rise%2Frun=-1%2F2


which shows us that the rise is -1 and the run is 2. This means that to go from point to point, we can go down 1 and over 2



So starting at , go down 1 unit


and to the right 2 units to get to the next point



Now draw a line through these points to graph y=-%281%2F2%29x-1%2F4

So this is the graph of y=-%281%2F2%29x-1%2F4 through the points and


absolute-value/122134: I don't know the absolute value of -10. So can you please help me and also explain it to me. THANK YOU!!!!!
1 solutions

Answer 89671 by jim_thompson5910(28715) About Me  on 2008-01-23 19:39:33 (Show Source):
You can put this solution on YOUR website!
Since the distance from -10 to 0 is 10 units, this means abs%28-10%29=10


Remember, absolute value refers to distance. So it only makes sense to have positive answers.


Expressions-with-variables/122150: I think this is the right section. My father in law is trying to help someone with their homework and called me. My algebra memory has faded :)
solve for x
x=zb-zk^2 (or, in english, x equals zb minus zk squared)
1 solutions

Answer 89669 by jim_thompson5910(28715) About Me  on 2008-01-23 19:30:54 (Show Source):
You can put this solution on YOUR website!
Since x is alone on the left side it is already isolated and solved for. So no work needs to be done if you want to solve for x. Do you want to solve for another variable?


Graphs/122142: solve the following systems by using either addition or substitution. if a unique solution does not exist, state whether the system is dependent of inconsistent.
10x+2y=7
y=-5x+3
1 solutions

Answer 89666 by jim_thompson5910(28715) About Me  on 2008-01-23 19:13:05 (Show Source):
You can put this solution on YOUR website!
Start with the given system
10x%2B2y=7
y=-5x%2B3



10x%2B2%28-5x%2B3%29=7 Plug in y=-5x%2B3 into the first equation. In other words, replace each y with -5x%2B3. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


10x-10x%2B6=7 Distribute


6=7 Combine like terms on the left side


0=7-6Subtract 6 from both sides


0=1 Combine like terms on the right side


Since this equation is never true for any x value, this means there are no solutions. So the system is inconsistent.


Number-Line/122135: The problem is this:
-5 is greater than/equal to x-6
1 solutions

Answer 89661 by jim_thompson5910(28715) About Me  on 2008-01-23 18:53:01 (Show Source):
You can put this solution on YOUR website!

-5%3E=x-6 Start with the given inequality



0%3E=x-6%2B5Add 5 to both sides


-x%3E=-6%2B5 Subtract x from both sides


-x%3E=-1 Combine like terms on the right side


x%3C=%28-1%29%2F%28-1%29 Divide both sides by -1 to isolate x (note: Remember, dividing both sides by a negative number flips the inequality sign)



x%3C=1 Divide

--------------------------------------------------------------
Answer:
So our answer is x%3C=1



Trigonometry-basics/122078: #10
Find the coordinates [r, theta] of all points of intersection:
r = 2sin(theta) and r = 1

a) [½, pi/3] and [½, 5pi/3]
b) [½, pi/6] and [½, 5pi/6]
c) [1, pi/3] and [1, 5pi/3]
d) [1, pi/6] and [1, 5pi/6]
e) None of these

1 solutions

Answer 89607 by jim_thompson5910(28715) About Me  on 2008-01-23 14:29:00 (Show Source):
You can put this solution on YOUR website!
Start with the given set of equations







Plug in r=1 into the first equation




Divide both sides by 2



Take the arcsine of both sides to isolate



or Take the arcsine of 1%2F2 to get pi%2F6 and 5pi%2F6:






So because the answer format is this means we have the solutions:


and


So the answer is D)


Note: Since the second equation is r=1, this means that the first coordinate (which is r) is also 1. So the answers will look like (1,?) and (1,?). So if you had no idea what to do, you could easily eliminate possible answers a) and b)


Quadratic-relations-and-conic-sections/122072: #9
Identify x = 4sint
y = 5cost

a) circle
b) parabola
c) ellipse
d) hyperbola
e) none of these

1 solutions

Answer 89606 by jim_thompson5910(28715) About Me  on 2008-01-23 14:10:01 (Show Source):
You can put this solution on YOUR website!
x=4%2Asin%28t%29 Start with the first parametric equation

x%2F4=sin%28t%29 Divide both sides by 4 to isolate sin%28t%29.


y=5%2Acos%28t%29 Start with the second parametric equation

x%2F5=sin%28t%29 Divide both sides by 5 to isolate cos%28t%29.
Now we're going to use the trig identity:

%28sin%28t%29%29%5E2%2B%28cos%28t%29%29%5E2=1

%28x%2F4%29%5E2%2B%28y%2F5%29%5E2=1 Replace sin%28t%29 with x%2F4. Replace cos%28t%29 with y%2F5. This is why we isolated sine and cosine.

x%5E2%2F16%2By%5E2%2F25=1 Square x%2F4 to get x%5E2%2F16. Square y%2F5 to get y%5E2%2F25.



Notice how the equation is now in the form %28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1 (note: h and k are equal to zero in this case)


So this shows us that x%5E2%2F16%2By%5E2%2F25=1 graphs an ellipse (since the above equation is the general equation of an ellipse).

So this means that the two parametric equations also graph an ellipse. So the answer is C)


Complex_Numbers/122065: Find (1 / sq. rt. 2 + i / sq. rt. 2) ^ 8

a.) -8
b.) 256
c.) 8
d.) 1
e.) None of these

1 solutions

Answer 89603 by jim_thompson5910(28715) About Me  on 2008-01-23 13:50:16 (Show Source):
You can put this solution on YOUR website!
%281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8 Start with the given expression


It's very useful to note that cos%28pi%2F4%29=1%2Fsqrt%282%29 and sin%28pi%2F4%29=1%2Fsqrt%282%29 . So the expression is equivalent to


%28cos%28pi%2F4%29%2Bi%2Asin%28pi%2F4%29%29%5E8


Now we're going to use De Moivre's theorem to solve this problem.

Remember, De Moivre's theorem states: %28cos%28x%29%2Bi%2Asin%28x%29%29%5En=cos%28n%2Ax%29%2Bi%2Asin%28n%2Ax%29

So using De Moivre's theorem we get


cos%288%2Api%2F4%29%2Bi%2Asin%288%2Api%2F4%29



cos%282pi%29%2Bi%2Asin%282pi%29 Multiply 8 and pi%2F4 to get 8pi%2F4. Now reduce to get 2pi



1%2B0i Take the cosine of 2pi to get 1. Take the sine of 2pi to get 0.


1 Remove the zero term


So %281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8 simplifies to 1.

In other words, %281%2Fsqrt%282%29%2Bi%2Fsqrt%282%29%29%5E8=1



So the answer is D)


Linear-equations/122018: Find the equation of the line through the two points (5,3) and (-7,7).

1 solutions

Answer 89574 by jim_thompson5910(28715) About Me  on 2008-01-23 10:34:54 (Show Source):
You can put this solution on YOUR website!
First lets find the slope through the points (5,3) and (-7,7)

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula (note: is the first point (5,3) and is the second point (-7,7))

m=%287-3%29%2F%28-7-5%29 Plug in y%5B2%5D=7,y%5B1%5D=3,x%5B2%5D=-7,x%5B1%5D=5 (these are the coordinates of given points)

m=+4%2F-12 Subtract the terms in the numerator 7-3 to get 4. Subtract the terms in the denominator -7-5 to get -12


m=-1%2F3 Reduce

So the slope is
m=-1%2F3

------------------------------------------------


Now let's use the point-slope formula to find the equation of the line:



------Point-Slope Formula------
y-y%5B1%5D=m%28x-x%5B1%5D%29 where m is the slope, and is one of the given points

So lets use the Point-Slope Formula to find the equation of the line

y-3=%28-1%2F3%29%28x-5%29 Plug in m=-1%2F3, x%5B1%5D=5, and y%5B1%5D=3 (these values are given)


y-3=%28-1%2F3%29x%2B%28-1%2F3%29%28-5%29 Distribute -1%2F3

y-3=%28-1%2F3%29x%2B5%2F3 Multiply -1%2F3 and -5 to get 5%2F3

y=%28-1%2F3%29x%2B5%2F3%2B3 Add 3 to both sides to isolate y

y=%28-1%2F3%29x%2B14%2F3 Combine like terms 5%2F3 and 3 to get 14%2F3 (note: if you need help with combining fractions, check out this solver)


------------------------------------------------------------------------------------------------------------
Answer:


So the equation of the line which goes through the points (5,3) and (-7,7) is:y=%28-1%2F3%29x%2B14%2F3

The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=-1%2F3 and the y-intercept is b=14%2F3

Notice if we graph the equation y=%28-1%2F3%29x%2B14%2F3 and plot the points (5,3) and (-7,7), we get this: (note: if you need help with graphing, check out this solver)

Graph of y=%28-1%2F3%29x%2B14%2F3 through the points (5,3) and (-7,7)

Notice how the two points lie on the line. This graphically verifies our answer.


Pythagorean-theorem/121959: 1. A customer wants to make a teepee in his backyard for his children. He plans to use lengths of PVC plumbing pipe for the supports on the teepee, and he wants the teepee to be 12 feet across and 8 feet tall. How long should the PVC plumbing pipe be?
1 solutions

Answer 89539 by jim_thompson5910(28715) About Me  on 2008-01-23 00:32:37 (Show Source):
You can put this solution on YOUR website!
If we cut the triangle in half vertically down the middle, we get this triangle:


Since we can see that the triangle has legs of 8 and 6 with a hypotenuse of x, we can use Pythagoreans theorem to find the unknown side.


Pythagoreans theorem:

a%5E2%2Bb%5E2=c%5E2 where a and b are the legs of the triangle and c is the hypotenuse



8%5E2%2B6%5E2=x%5E2 Plug in a=8, b=6, and c=x. Now lets solve for x


6+4+%2B+3+6+=++x++%5E+2 Square each individual term



1+0+0+=++x++%5E+2 Combine like terms


s+q+r+t+%28+1+0+0+%29+=+s+q+r+t+%28++x++%5E+2+%29 Take the square root of both sides


10=x Simplify the square root

So the hypotenuse of this triangle is 10


Since we cut the triangle in half, this means the other triangle's hypotenuse also has a length of 10

After putting the two triangles back together, we have this triangle:


Photobucket


Since the figure was pointing to one side, I'm assuming that the problem is asking about one side. So the length of one pipe is 10 ft.


Trigonometry-basics/121956: 7) For x E [0,2pi), solve: cos2x = cosx
a) 2 pi/3, 4pi/3 and pi
b) 2 pi/3, 4 pi/3 and 0
c) Pi/3, 5pi/3 and 0
d) Pi/6, 5pi/6 and pi
e) 5pi/6, 7pi/6 and pi
1 solutions

Answer 89537 by jim_thompson5910(28715) About Me  on 2008-01-23 00:08:41 (Show Source):
You can put this solution on YOUR website!
Start with the given equation

Replace with . Note: I'm using the identity

Subtract cos%28x%29 from both sides

Rearrange the terms

Now let u=cos%28x%29

Replace each cos%28x%29 with u

%28u-1%29%282u%2B1%29=0 Factor the left side

Now set each factor equal to zero

u-1=0 or 2u%2B1=0

Now solve for u in each case

u=1 or u=-1%2F2

Now remember we let u=cos%28x%29. So this means

cos%28x%29=1 or cos%28x%29=-1%2F2

So let's solve cos%28x%29=1 to get x=0 or x=2pi. However, since 2pi is excluded the only solution for cos%28x%29=1 is x=0

Now let's solve cos%28x%29=-1%2F2 to get x=2pi%2F3 or x=4pi%2F3

So putting these solutions together, we get:

x=0, x=2pi%2F3 or x=4pi%2F3


So this means the answer is B)


Trigonometry-basics/121955: 6) find csc(arctan 8/15)
a) 17/8
b) 8/17
c) 15/17
d) 17/15
e) Undefined
1 solutions

Answer 89535 by jim_thompson5910(28715) About Me  on 2008-01-23 00:01:59 (Show Source):
You can put this solution on YOUR website!
First a triangle with legs of 8 and 15. Let x be the angle we'll refer to.




By using pythagorean's theorem, we find that the hypotenuse is 17 units





Since tan%28x%29=opposite%2Fadjacent this means x=arctan%288%2F15%29 (notice how the arctangent is gives you an angle)

Now remember sin%28x%29=opposite%2Fhypotenuse and csc%28x%29=hypotenuse%2Fopposite (remember the cosecant and sine function are reciprocals of each other)

So csc%28x%29=17%2F8


which also means

csc%28arctan%288%2F15%29%29=17%2F8

So the answer is A)


Trigonometry-basics/121954: 5) Find the period of f(x) = 3 - 2cos(3x+pi)
a) 2 pi / 3
b) Pi / 3
c) Pi / 6
d) Pi
e) 2 pi
1 solutions

Answer 89533 by jim_thompson5910(28715) About Me  on 2008-01-22 23:55:31 (Show Source):
You can put this solution on YOUR website!

The general form of cosine is:
y+=+Acos%28Bx+%2B+C%29+%2B+D
where the period T=2pi%2FB+

So for the trig function f%28x%29=3+-+2cos%283x%2Bpi%29 which also looks like f%28x%29=+-+2cos%283x%2Bpi%29%2B3. Notice how 3x matches up with Bx, so Bx=3x which means B=3

T=2pi%2F3+ Now simply plug in B=3 into the period formula

So the period is T=2pi%2F3+

So the answer is A)


Quadratic-relations-and-conic-sections/121913: Name the vertex for the parabol with equation
y= 3x^2-12x+16
1 solutions

Answer 89531 by jim_thompson5910(28715) About Me  on 2008-01-22 23:50:55 (Show Source):
You can put this solution on YOUR website!
To find the vertex, we first need to find the axis of symmetry (ie the x-coordinate of the vertex)
To find the axis of symmetry, use this formula:

x=-b%2F%282a%29

From the equation y=3x%5E2-12x%2B16 we can see that a=3 and b=-12

x=%28--12%29%2F%282%2A3%29 Plug in b=-12 and a=3


x=12%2F%282%2A3%29 Negate -12 to get 12


x=%2812%29%2F6 Multiply 2 and 3 to get 6



x=2 Reduce


So the axis of symmetry is x=2


So the x-coordinate of the vertex is x=2. Lets plug this into the equation to find the y-coordinate of the vertex.



y=3x%5E2-12x%2B16 Start with the given polynomial


y=3%282%29%5E2-12%282%29%2B16 Plug in x=2


y=3%284%29-12%282%29%2B16 Raise 2 to the second power to get 4


y=12-12%282%29%2B16 Multiply 3 by 4 to get 12


y=12-24%2B16 Multiply 12 by 2 to get 24


y=4 Now combine like terms


So the vertex is (2,4)


Polynomials-and-rational-expressions/121920: Solve for a.
6a(a+3) = 2a(3a+5)+16
1 solutions

Answer 89530 by jim_thompson5910(28715) About Me  on 2008-01-22 23:47:43 (Show Source):
You can put this solution on YOUR website!
6a%28a%2B3%29+=+2a%283a%2B5%29%2B16 Start with the given equation


6a%5E2%2B18a+=+6a%5E2%2B10a%2B16 Distribute



6a%5E2%2B18a+-+6a%5E2-10a-16=0 Get all of the terms to the left side



8a-16=0 Combine like terms



8a=0%2B16Add 16 to both sides


8a=16 Combine like terms on the right side


a=%2816%29%2F%288%29 Divide both sides by 8 to isolate a



a=2 Divide

--------------------------------------------------------------
Answer:
So our answer is a=2




Linear-equations/121921: I need help finding slope of line passing through (-3,3) and (-3,-3)
1 solutions

Answer 89528 by jim_thompson5910(28715) About Me  on 2008-01-22 23:45:05 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Finding the slope


Slope of the line through the points (-3, 3) and (-3, -3)



m+=+%28y%5B2%5D+-+y%5B1%5D%29%2F%28x%5B2%5D+-+x%5B1%5D%29


m+=+%28-3+-+3%29%2F%28-3+-+-3%29


m+=+%28-6%29%2F%280%29


Since you CANNOT divide by 0, this means that the slope of the line is undefined.


Answer: The slope of the line is undefined.



Graphs/121930: solve the following systems by addition. If a unique solution does not exist, state whether the system is inconsistent or dependent.
2x+3y=1
5x+3y=16
1 solutions

Answer 89525 by jim_thompson5910(28715) About Me  on 2008-01-22 23:44:08 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition


Lets start with the given system of linear equations

2%2Ax%2B3%2Ay=1
5%2Ax%2B3%2Ay=16

In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).

So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.

So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 2 and 5 to some equal number, we could try to get them to the LCM.

Since the LCM of 2 and 5 is 10, we need to multiply both sides of the top equation by 5 and multiply both sides of the bottom equation by -2 like this:

5%2A%282%2Ax%2B3%2Ay%29=%281%29%2A5 Multiply the top equation (both sides) by 5
-2%2A%285%2Ax%2B3%2Ay%29=%2816%29%2A-2 Multiply the bottom equation (both sides) by -2


So after multiplying we get this:
10%2Ax%2B15%2Ay=5
-10%2Ax-6%2Ay=-32

Notice how 10 and -10 add to zero (ie 10%2B-10=0)


Now add the equations together. In order to add 2 equations, group like terms and combine them
%2810%2Ax-10%2Ax%29%2B%2815%2Ay-6%2Ay%29=5-32

%2810-10%29%2Ax%2B%2815-6%29y=5-32

cross%2810%2B-10%29%2Ax%2B%2815-6%29%2Ay=5-32 Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.



So after adding and canceling out the x terms we're left with:

9%2Ay=-27

y=-27%2F9 Divide both sides by 9 to solve for y



y=-3 Reduce


Now plug this answer into the top equation 2%2Ax%2B3%2Ay=1 to solve for x

2%2Ax%2B3%28-3%29=1 Plug in y=-3


2%2Ax-9=1 Multiply



2%2Ax=1%2B9 Subtract -9 from both sides

2%2Ax=10 Combine the terms on the right side

cross%28%281%2F2%29%282%29%29%2Ax=%2810%29%281%2F2%29 Multiply both sides by 1%2F2. This will cancel out 2 on the left side.


x=5 Multiply the terms on the right side


So our answer is

x=5, y=-3

which also looks like

(5, -3)

Notice if we graph the equations (if you need help with graphing, check out this solver)

2%2Ax%2B3%2Ay=1
5%2Ax%2B3%2Ay=16

we get



graph of 2%2Ax%2B3%2Ay=1 (red) 5%2Ax%2B3%2Ay=16 (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).


and we can see that the two equations intersect at (5,-3). This verifies our answer.


Pythagorean-theorem/121931: A 15 feet ladder is 5 feet away from a wall. How far above the floor is the top of the ladder?
1 solutions

Answer 89524 by jim_thompson5910(28715) About Me  on 2008-01-22 23:43:20 (Show Source):
You can put this solution on YOUR website!
We basically have this triangle set up:


Since we can see that the triangle has legs of x and 5 with a hypotenuse of 15, we can use Pythagoreans theorem to find the unknown side.


Pythagoreans theorem:

a%5E2%2Bb%5E2=c%5E2 where a and b are the legs of the triangle and c is the hypotenuse



x%5E2%2B5%5E2=15%5E2 Plug in a=x, b=5, and c=15. Now lets solve for x


+x++%5E+2+%2B+2+5+=+2+2+5 Square each individual term



+x++%5E+2+=+2+2+5+-+2+5 Subtract 25 from both sides


+x++%5E+2+=+2+0+0 Combine like terms


s+q+r+t+%28++x++%5E+2+%29+=+s+q+r+t+%28+2+0+0+%29 Take the square root of both sides



x=10%2Asqrt%282%29 Simplify the square root

Which approximates to...
x+=+1+4+.+1+4+2+1+3+5+6+2+3+7+3+1

So our answer is
x+=+1+4+.+1+4+2+1+3+5+6+2+3+7+3+1



So the top of the ladder is about 14.14 feet about the floor


Quadratic_Equations/121932: solve the following systems by addition. If a unique solution does not exist, state whether the system is inconsistent or dependent.
X+5Y=10
-2X-10Y=-20
1 solutions

Answer 89523 by jim_thompson5910(28715) About Me  on 2008-01-22 23:41:53 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Solving a linear system of equations by subsitution


Lets start with the given system of linear equations

1%2Ax%2B5%2Ay=10
-2%2Ax-10%2Ay=-20

Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to choose y.

Solve for y for the first equation

5%2Ay=10-1%2AxSubtract 1%2Ax from both sides

y=%2810-1%2Ax%29%2F5 Divide both sides by 5.


Which breaks down and reduces to



y=2-%281%2F5%29%2Ax Now we've fully isolated y

Since y equals 2-%281%2F5%29%2Ax we can substitute the expression 2-%281%2F5%29%2Ax into y of the 2nd equation. This will eliminate y so we can solve for x.


-2%2Ax%2B-10%2Ahighlight%28%282-%281%2F5%29%2Ax%29%29=-20 Replace y with 2-%281%2F5%29%2Ax. Since this eliminates y, we can now solve for x.

-2%2Ax-10%2A%282%29-10%28-1%2F5%29x=-20 Distribute -10 to 2-%281%2F5%29%2Ax

-2%2Ax-20%2B%2810%2F5%29%2Ax=-20 Multiply



-2%2Ax-20%2B2%2Ax=-20 Reduce any fractions

-2%2Ax%2B2%2Ax=-20%2B20Add 20 to both sides


-2%2Ax%2B2%2Ax=0 Combine the terms on the right side



0%2Ax=0 Now combine the terms on the left side.
0=0 Since this expression is true for any x, we have an identity.


So there are an infinite number solutions. The simple reason is the 2 equations represent 2 lines that overlap each other. So they intersect each other at an infinite number of points.

If we graph 1%2Ax%2B5%2Ay=10 and -2%2Ax-10%2Ay=-20 we get

+graph%28+500%2C+600%2C+-6%2C+5%2C+-10%2C+10%2C+%2810-1%2Ax%29%2F5%29+ graph of 1%2Ax%2B5%2Ay=10


+graph%28+500%2C+600%2C+-6%2C+5%2C+-10%2C+10%2C+%28-20--2%2Ax%29%2F-10+%29+ graph of -2%2Ax-10%2Ay=-20 (hint: you may have to solve for y to graph these)

we can see that these two lines are the same. So this system is dependent


Linear-systems/121939: I need help with the following problems:
y = 2x + 6
y = -x -3

y - 3x = 9
2y + x = 4


y + 4 = 2x
6x - 3y = 12




1 solutions

Answer 89522 by jim_thompson5910(28715) About Me  on 2008-01-22 23:40:57 (Show Source):
You can put this solution on YOUR website!
#1


Start with the given system
y=2x%2B6
y=-x-3



%28-x-3%29=2x%2B6 Plug in y=-x-3 into the first equation. In other words, replace each y with -x-3. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


%28-x-3%29=2x%2B6 Distribute


-x-3=2x%2B6 Combine like terms on the left side


-x=2x%2B6%2B3Add 3 to both sides


-x-2x=6%2B3 Subtract 2x from both sides


-3x=6%2B3 Combine like terms on the left side


-3x=9 Combine like terms on the right side


x=%289%29%2F%28-3%29 Divide both sides by -3 to isolate x



x=-3 Divide




Now that we know that x=-3, we can plug this into y=-x-3 to find y



y=-%28-3%29-3 Substitute -3 for each x


y=0 Simplify


So our answer is x=-3 and y=0 which also looks like



Notice if we graph the two equations, we can see that their intersection is at . So this verifies our answer.


+graph%28+500%2C+500%2C+-5%2C+5%2C+-5%2C+5%2C+2x%2B6%2C+-x-3%29+ Graph of y=2x%2B6 (red) and y=-x-3 (green)






#2
Solved by pluggable solver: Solving a linear system of equations by subsitution


Lets start with the given system of linear equations

-3%2Ax%2B1%2Ay=9
1%2Ax%2B2%2Ay=4

Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to choose y.

Solve for y for the first equation

1%2Ay=9%2B3%2AxAdd 3%2Ax to both sides

y=%289%2B3%2Ax%29 Divide both sides by 1.


Which breaks down and reduces to



y=9%2B3%2Ax Now we've fully isolated y

Since y equals 9%2B3%2Ax we can substitute the expression 9%2B3%2Ax into y of the 2nd equation. This will eliminate y so we can solve for x.


1%2Ax%2B2%2Ahighlight%28%289%2B3%2Ax%29%29=4 Replace y with 9%2B3%2Ax. Since this eliminates y, we can now solve for x.

1%2Ax%2B2%2A%289%29%2B2%283%29x=4 Distribute 2 to 9%2B3%2Ax

1%2Ax%2B18%2B6%2Ax=4 Multiply



1%2Ax%2B18%2B6%2Ax=4 Reduce any fractions

1%2Ax%2B6%2Ax=4-18 Subtract 18 from both sides


1%2Ax%2B6%2Ax=-14 Combine the terms on the right side



7%2Ax=-14 Now combine the terms on the left side.


cross%28%281%2F7%29%287%2F1%29%29x=%28-14%2F1%29%281%2F7%29 Multiply both sides by 1%2F7. This will cancel out 7%2F1 and isolate x

So when we multiply -14%2F1 and 1%2F7 (and simplify) we get



x=-2 <---------------------------------One answer

Now that we know that x=-2, lets substitute that in for x to solve for y

1%28-2%29%2B2%2Ay=4 Plug in x=-2 into the 2nd equation

-2%2B2%2Ay=4 Multiply

2%2Ay=4%2B2Add 2 to both sides

2%2Ay=6 Combine the terms on the right side

cross%28%281%2F2%29%282%29%29%2Ay=%286%2F1%29%281%2F2%29 Multiply both sides by 1%2F2. This will cancel out 2 on the left side.

y=6%2F2 Multiply the terms on the right side


y=3 Reduce


So this is the other answer


y=3<---------------------------------Other answer


So our solution is

x=-2 and y=3

which can also look like

(-2,3)

Notice if we graph the equations (if you need help with graphing, check out this solver)

-3%2Ax%2B1%2Ay=9
1%2Ax%2B2%2Ay=4

we get


graph of -3%2Ax%2B1%2Ay=9 (red) and 1%2Ax%2B2%2Ay=4 (green) (hint: you may have to solve for y to graph these) intersecting at the blue circle.


and we can see that the two equations intersect at (-2,3). This verifies our answer.


-----------------------------------------------------------------------------------------------
Check:

Plug in (-2,3) into the system of equations


Let x=-2 and y=3. Now plug those values into the equation -3%2Ax%2B1%2Ay=9

-3%2A%28-2%29%2B1%2A%283%29=9 Plug in x=-2 and y=3


6%2B3=9 Multiply


9=9 Add


9=9 Reduce. Since this equation is true the solution works.


So the solution (-2,3) satisfies -3%2Ax%2B1%2Ay=9



Let x=-2 and y=3. Now plug those values into the equation 1%2Ax%2B2%2Ay=4

1%2A%28-2%29%2B2%2A%283%29=4 Plug in x=-2 and y=3


-2%2B6=4 Multiply


4=4 Add


4=4 Reduce. Since this equation is true the solution works.


So the solution (-2,3) satisfies 1%2Ax%2B2%2Ay=4


Since the solution (-2,3) satisfies the system of equations


-3%2Ax%2B1%2Ay=9
1%2Ax%2B2%2Ay=4


this verifies our answer.










#3

y+%2B+4+=+2x Start with the first equation


y=+2x-4 Solve for y by subtracting 4 from both sides




Start with the given system
6x-3y=12
y=2x-4



6x-3%282x-4%29=12 Plug in y=2x-4 into the first equation. In other words, replace each y with 2x-4. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


6x-6x%2B12=12 Distribute


12=12 Combine like terms on the left side


0=12-12Subtract 12 from both sides


0=0 Combine like terms on the right side


0=0 Simplify

Since this equation is always true for any x value, this means x can equal any number. So there are an infinite number of solutions.


Graphs/121953: This question is from textbook
x+5/2=6
1 solutions

Answer 89518 by jim_thompson5910(28715) About Me  on 2008-01-22 23:35:47 (Show Source):
You can put this solution on YOUR website!

x%2B5%2F2=6 Start with the given equation



%282%29%28x%2B5%2F2%29=%282%29%286%29 Multiply both sides by the LCM of 2. This will eliminate the fractions (note: if you need help with finding the LCM, check out this solver)



2x%2B5=12 Distribute and multiply the LCM to each side



2x=12-5Subtract 5 from both sides


2x=7 Combine like terms on the right side


x=%287%29%2F%282%29 Divide both sides by 2 to isolate x




--------------------------------------------------------------
Answer:
So our answer is x=7%2F2 (which is approximately x=3.5 in decimal form)


Quadratic_Equations/121936: SOLVE BY SUBSTITUTION
5X-2Y=-5
Y-5X=3
1 solutions

Answer 89516 by jim_thompson5910(28715) About Me  on 2008-01-22 23:34:55 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Solving a linear system of equations by subsitution


Lets start with the given system of linear equations

5%2Ax-2%2Ay=-5
-5%2Ax%2B1%2Ay=3

Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to choose y.

Solve for y for the first equation

-2%2Ay=-5-5%2AxSubtract 5%2Ax from both sides

y=%28-5-5%2Ax%29%2F-2 Divide both sides by -2.


Which breaks down and reduces to



y=5%2F2%2B%285%2F2%29%2Ax Now we've fully isolated y

Since y equals 5%2F2%2B%285%2F2%29%2Ax we can substitute the expression 5%2F2%2B%285%2F2%29%2Ax into y of the 2nd equation. This will eliminate y so we can solve for x.


-5%2Ax%2B1%2Ahighlight%28%285%2F2%2B%285%2F2%29%2Ax%29%29=3 Replace y with 5%2F2%2B%285%2F2%29%2Ax. Since this eliminates y, we can now solve for x.

-5%2Ax%2B1%2A%285%2F2%29%2B1%285%2F2%29x=3 Distribute 1 to 5%2F2%2B%285%2F2%29%2Ax

-5%2Ax%2B5%2F2%2B%285%2F2%29%2Ax=3 Multiply



-5%2Ax%2B5%2F2%2B%285%2F2%29%2Ax=3 Reduce any fractions

-5%2Ax%2B%285%2F2%29%2Ax=3-5%2F2 Subtract 5%2F2 from both sides


-5%2Ax%2B%285%2F2%29%2Ax=6%2F2-5%2F2 Make 3 into a fraction with a denominator of 2


-5%2Ax%2B%285%2F2%29%2Ax=1%2F2 Combine the terms on the right side



%28-10%2F2%29%2Ax%2B%285%2F2%29x=1%2F2 Make -5 into a fraction with a denominator of 2

%28-5%2F2%29%2Ax=1%2F2 Now combine the terms on the left side.


cross%28%282%2F-5%29%28-5%2F2%29%29x=%281%2F2%29%282%2F-5%29 Multiply both sides by 2%2F-5. This will cancel out -5%2F2 and isolate x

So when we multiply 1%2F2 and 2%2F-5 (and simplify) we get



x=-1%2F5 <---------------------------------One answer

Now that we know that x=-1%2F5, lets substitute that in for x to solve for y

-5%28-1%2F5%29%2B1%2Ay=3 Plug in x=-1%2F5 into the 2nd equation

1%2B1%2Ay=3 Multiply

1%2Ay=3-1Subtract 1 from both sides

1%2Ay=2 Combine the terms on the right side

cross%28%281%2F1%29%281%29%29%2Ay=%282%2F1%29%281%2F1%29 Multiply both sides by 1%2F1. This will cancel out 1 on the left side.

y=2%2F1 Multiply the terms on the right side


y=2 Reduce


So this is the other answer


y=2<---------------------------------Other answer


So our solution is

x=-1%2F5 and y=2

which can also look like

(-1%2F5,2)

Notice if we graph the equations (if you need help with graphing, check out this solver)

5%2Ax-2%2Ay=-5
-5%2Ax%2B1%2Ay=3

we get


graph of 5%2Ax-2%2Ay=-5 (red) and -5%2Ax%2B1%2Ay=3 (green) (hint: you may have to solve for y to graph these) intersecting at the blue circle.


and we can see that the two equations intersect at (-1%2F5,2). This verifies our answer.


-----------------------------------------------------------------------------------------------
Check:

Plug in (-1%2F5,2) into the system of equations


Let x=-1%2F5 and y=2. Now plug those values into the equation 5%2Ax-2%2Ay=-5

5%2A%28-1%2F5%29-2%2A%282%29=-5 Plug in x=-1%2F5 and y=2


-5%2F5-4=-5 Multiply


-25%2F5=-5 Add


-5=-5 Reduce. Since this equation is true the solution works.


So the solution (-1%2F5,2) satisfies 5%2Ax-2%2Ay=-5



Let x=-1%2F5 and y=2. Now plug those values into the equation -5%2Ax%2B1%2Ay=3

-5%2A%28-1%2F5%29%2B1%2A%282%29=3 Plug in x=-1%2F5 and y=2


5%2F5%2B2=3 Multiply


15%2F5=3 Add


3=3 Reduce. Since this equation is true the solution works.


So the solution (-1%2F5,2) satisfies -5%2Ax%2B1%2Ay=3


Since the solution (-1%2F5,2) satisfies the system of equations


5%2Ax-2%2Ay=-5
-5%2Ax%2B1%2Ay=3


this verifies our answer.