New!
Get regular updates about newly solved problems
via algebra.com's RSS system.
Recent problems solved by 'jim_thompson5910'
jim_thompson5910 answered: 28535 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, >>Next
Signed-numbers/181960: y=1/4x+5 1 solutions
Answer 136580 by jim_thompson5910(28546) on 2009-02-14 19:52:25 (Show Source):
You can put this solution on YOUR website!Do you want to graph this? Please post full instructions.
If you want to graph, then...
Looking at  we can see that the equation is in slope-intercept form  where the slope is  and the y-intercept is
Since  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
Also, because the slope is  , this means:
which shows us that the rise is 1 and the run is 4. This means that to go from point to point, we can go up 1 and over 4
So starting at ) , go up 1 unit
and to the right 4 units to get to the next point
Now draw a line through these points to graph
 So this is the graph of  through the points ) and
|
Linear-systems/181961: Find the values of x and y that solve the following systems of equations.
6x+7y=-5
4x+3y=-15 1 solutions
Answer 136579 by jim_thompson5910(28546) on 2009-02-14 19:50:18 (Show Source):
You can put this solution on YOUR website!
Start with the given system of equations:
 Multiply the both sides of the first equation by 2.
 Distribute and multiply.
 Multiply the both sides of the second equation by -3.
 Distribute and multiply.
So we have the new system of equations:
Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:
 Group like terms.
 Combine like terms.
 Simplify.
 Divide both sides by  to isolate  .
 Reduce.
------------------------------------------------------------------
 Now go back to the first equation.
 Plug in  .
 Multiply.
 Subtract  from both sides.
 Combine like terms on the right side.
 Divide both sides by  to isolate  .
 Reduce.
So our answer is  and  .
Which form the ordered pair ) .
This means that the system is consistent and independent.
Notice when we graph the equations, we see that they intersect at ) . So this visually verifies our answer.
 Graph of  (red) and  (green)
|
Polynomials-and-rational-expressions/181957: 46. Factor completely. -3t^3+ 3t^2-6t
60. Factor polynomial completely. 10a^2+ab-2b^2
80. Factor completely. 4m^2+20m+25
90. Factor each polynomial completely, given that the binomial Following it is a factor of the polynomial. x^3-4x^2-3x-10, x-5
102. Solve each equation. t2+1=13/6t
1 solutions
Answer 136578 by jim_thompson5910(28546) on 2009-02-14 19:49:08 (Show Source):
You can put this solution on YOUR website!I'll do the first three to get you started:
# 46
 Start with the given expression
 Factor out the GCF
So  factors to
================================================
# 60
Looking at  we can see that the first term is  and the last term is  where the coefficients are 10 and -2 respectively.
Now multiply the first coefficient 10 and the last coefficient -2 to get -20. Now what two numbers multiply to -20 and add to the middle coefficient 1? Let's list all of the factors of -20:
Factors of -20:
1,2,4,5,10,20
-1,-2,-4,-5,-10,-20 ...List the negative factors as well. This will allow us to find all possible combinations
These factors pair up and multiply to -20
(1)*(-20)
(2)*(-10)
(4)*(-5)
(-1)*(20)
(-2)*(10)
(-4)*(5)
note: remember, the product of a negative and a positive number is a negative number
Now which of these pairs add to 1? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 1
| First Number | Second Number | Sum | | 1 | -20 | 1+(-20)=-19 | | 2 | -10 | 2+(-10)=-8 | | 4 | -5 | 4+(-5)=-1 | | -1 | 20 | -1+20=19 | | -2 | 10 | -2+10=8 | | -4 | 5 | -4+5=1 |
From this list we can see that -4 and 5 add up to 1 and multiply to -20
Now looking at the expression  , replace  with  (notice  adds up to  . So it is equivalent to  )
Now let's factor  by grouping:
 Group like terms
 Factor out the GCF of  out of the first group. Factor out the GCF of  out of the second group
 Since we have a common term of  , we can combine like terms
So  factors to
So this also means that  factors to  (since  is equivalent to  )
------------------------------------------------------------
Answer:
So  factors to
================================================
# 80
Looking at  we can see that the first term is  and the last term is  where the coefficients are 4 and 25 respectively.
Now multiply the first coefficient 4 and the last coefficient 25 to get 100. Now what two numbers multiply to 100 and add to the middle coefficient 20? Let's list all of the factors of 100:
Factors of 100:
1,2,4,5,10,20,25,50
-1,-2,-4,-5,-10,-20,-25,-50 ...List the negative factors as well. This will allow us to find all possible combinations
These factors pair up and multiply to 100
1*100
2*50
4*25
5*20
10*10
(-1)*(-100)
(-2)*(-50)
(-4)*(-25)
(-5)*(-20)
(-10)*(-10)
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to 20? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 20
| First Number | Second Number | Sum | | 1 | 100 | 1+100=101 | | 2 | 50 | 2+50=52 | | 4 | 25 | 4+25=29 | | 5 | 20 | 5+20=25 | | 10 | 10 | 10+10=20 | | -1 | -100 | -1+(-100)=-101 | | -2 | -50 | -2+(-50)=-52 | | -4 | -25 | -4+(-25)=-29 | | -5 | -20 | -5+(-20)=-25 | | -10 | -10 | -10+(-10)=-20 |
From this list we can see that 10 and 10 add up to 20 and multiply to 100
Now looking at the expression  , replace  with  (notice  adds up to  . So it is equivalent to  )
Now let's factor  by grouping:
 Group like terms
 Factor out the GCF of  out of the first group. Factor out the GCF of  out of the second group
 Since we have a common term of  , we can combine like terms
So  factors to
So this also means that  factors to  (since  is equivalent to  )
note:  is equivalent to  since the term  occurs twice. So  also factors to
------------------------------------------------------------
Answer:
So  factors to
|
Signed-numbers/181958: -2(x+5)=5x+46 1 solutions
Answer 136577 by jim_thompson5910(28546) on 2009-02-14 19:42:37 (Show Source):
You can put this solution on YOUR website!
 Start with the given equation.
 Distribute.
 Add  to both sides.
 Subtract  from both sides.
 Combine like terms on the left side.
 Combine like terms on the right side.
 Divide both sides by  to isolate  .
 Reduce.
----------------------------------------------------------------------
Answer:
So the answer is
|
Polynomials-and-rational-expressions/181956: Factor each polynomial a^2-2a-35
1 solutions
Answer 136576 by jim_thompson5910(28546) on 2009-02-14 19:33:03 (Show Source):
You can put this solution on YOUR website!
Looking at the expression  , we can see that the first coefficient is  , the second coefficient is  , and the last term is  .
Now multiply the first coefficient  by the last term  to get  .
Now the question is: what two whole numbers multiply to  (the previous product) and add to the second coefficient  ?
To find these two numbers, we need to list all of the factors of  (the previous product).
Factors of  :
1,5,7,35
-1,-5,-7,-35
Note: list the negative of each factor. This will allow us to find all possible combinations.
These factors pair up and multiply to  .
1*(-35)
5*(-7)
(-1)*(35)
(-5)*(7)
Now let's add up each pair of factors to see if one pair adds to the middle coefficient  :
| First Number | Second Number | Sum | | 1 | -35 | 1+(-35)=-34 | | 5 | -7 | 5+(-7)=-2 | | -1 | 35 | -1+35=34 | | -5 | 7 | -5+7=2 |
From the table, we can see that the two numbers  and  add to  (the middle coefficient).
So the two numbers  and  both multiply to and add to
Now replace the middle term  with  . Remember,  and  add to  . So this shows us that  .
 Replace the second term  with  .
 Group the terms into two pairs.
 Factor out the GCF  from the first group.
 Factor out  from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.
 Combine like terms. Or factor out the common term
---------------------------------------------
Answer:
So  factors to  .
Note: you can check the answer by FOILing  to get  or by graphing the original expression and the answer (the two graphs should be identical).
|
Graphs/181947: graph the function f(x)=x^2-2 1 solutions
Answer 136569 by jim_thompson5910(28546) on 2009-02-14 18:04:08 (Show Source):
You can put this solution on YOUR website!
Table of Contents:
Step 1: Finding the Vertex
Step 2: Finding two points to left of axis of symmetry
Step 3: Reflecting two points to get points right of axis of symmetry
Step 4: Plotting the Points (with table)
Step 5: Graphing the Parabola
In order to graph  , we can follow the steps:
Step 1) Find the vertex (the vertex is the either the highest or lowest point on the graph). Also, the vertex is at the axis of symmetry of the parabola (ie it divides it in two).
Step 2) Once you have the vertex, find two points on the left side of the axis of symmetry (the line that vertically runs through the vertex).
Step 3) Reflect those two points over the axis of symmetry to get two more points on the right side of the axis of symmetry.
Step 4) Plot all of the points found (including the vertex).
Step 5) Draw a curve through all of the points to graph the parabola.
Let's go through these steps in detail
Jump to Top of Page
Step 1) Finding the vertex:
In order to find the vertex, we first need to find the x-coordinate of the vertex.
To find the x-coordinate of the vertex, use this formula:  .
 Start with the given formula.
From  , we can see that  ,  , and  .
 Plug in  and  .
 Multiply 2 and  to get  .
 Divide.
So the x-coordinate of the vertex is  . Note: this means that the axis of symmetry is also  .
Now that we know the x-coordinate of the vertex, we can use it to find the y-coordinate of the vertex.
 Start with the given equation.
 Plug in  .
 Square  to get  .
 Multiply  and  to get  .
 Combine like terms.
So the y-coordinate of the vertex is  .
So the vertex is ) .
---------------------------------------------------------------------
Jump to Top of Page
Step 2) Find two points to the left of the axis of symmetry:
Let's find the y value when
 Start with the given equation.
 Plug in  .
 Square  to get  .
 Multiply  and  to get  .
 Combine like terms.
So the first point to the left of the axis of symmetry is (-2,2)
---------------------
Let's find the y value when
 Start with the given equation.
 Plug in  .
 Square  to get  .
 Multiply  and  to get  .
 Combine like terms.
So the second point to the left of the axis of symmetry is (-1,-1)
---------------------------------------------------------------------
Jump to Top of Page
Step 3) Reflecting the two points over the axis of symmetry:
Now remember, the parabola is symmetrical about the axis of symmetry (which is  )
This means the y-value for  (which is one unit from the axis of symmetry) is equal to the y-value of  (which is also one unit from the axis of symmetry). So when  ,  which gives us the point (1,-1). So we essentially reflected the point (-1,-1) over to (1,-1).
Also, the y-value for  (which is two units from the axis of symmetry) is equal to the y-value of  (which is also two units from the axis of symmetry). So when  ,  which gives us the point (2,2). So we essentially reflected the point (-2,2) over to (2,2).
---------------------------------------------------------------------
Jump to Top of Page
Step 4) Plotting the points:
Now lets make a table of the values we have calculated:
Now let's plot the points:
---------------------------------------------------------------------
Jump to Top of Page
Step 5) Drawing a curve through all of the points:
Now draw a curve through all of the points to graph  :
 Graph of
|
Rational-functions/181944: This question is from textbook Algebra2
Complete parts a-c for each quadratic equation
a) find the value of the discriminant
b) describe the number and type of roots
c) find the exact solutions by using the Quadratic Formula
14) x^2+3x-3=0 1 solutions
Answer 136560 by jim_thompson5910(28546) on 2009-02-14 16:14:53 (Show Source):
You can put this solution on YOUR website!a)
From  we can see that  ,  , and
 Start with the discriminant formula.
 Plug in  ,  , and
 Square  to get
 Multiply  to get
 Rewrite  as
 Add  to  to get
So the discriminant is 21.
----------------------------------------------------
b)
From part a), we see that  . This means that  (ie the discriminant is positive)
Since the discriminant is greater than zero, this means that there are two real solutions.
So we can say that...
Type of Solution(s): Real
Number: 2 (these are distinct)
-----------------------------------------------------
c)
 Start with the given equation.
Notice we have a quadratic equation in the form of  where  ,  , and
Let's use the quadratic formula to solve for x
 Start with the quadratic formula
 Plug in  ,  , and
 Square  to get  .
 Multiply  to get
 Rewrite  as
 Add  to  to get
 Multiply  and  to get  .
 or  Break up the expression.
So the answers are  or
which approximate to  or
Notice how there are two real solutions. So this confirms our answer to part b)
|
Coordinate-system/181940: plot the graphs of the following functions:
1. f(x) = 5^x
2. f(x) = 4^x+2
3. f(x) = (1/3)^x
4. f(x) = log of x to the base of 5
could u please show me on graphs for at least two of them. thank you so much 1 solutions
Answer 136559 by jim_thompson5910(28546) on 2009-02-14 15:55:16 (Show Source):
You can put this solution on YOUR website!To graph ANY function, simply follow this basic routine:
1) Plug in any x value to find it's corresponding function value (or y value). This gives you an ordered pair (x,y)
2) Plot the points that you calculated from step 1
3) Draw a smooth connected through ALL of the points that you plotted in step 2
I'll do the first two to get you started. The other two follow the same basic outline.
# 1
In order to graph  , we need to plot a few points.
 Start with the given equation.
 Plug in  (note: you can start at any x-value).
 Raise 5 to the -2nd power to get  .
So when  ,  . So we have the point (-2,0.04).
----------------------------
 Start with the given equation.
 Plug in  .
 Raise 5 to the -1st power to get  .
So when  ,  . So we have the point (-1,0.2).
----------------------------
 Start with the given equation.
 Plug in  .
 Raise 5 to the 0th power to get  .
So when  ,  . So we have the point (0,1).
----------------------------
 Start with the given equation.
 Plug in  .
 Raise 5 to the 1st power to get  .
So when  ,  . So we have the point (1,5).
----------------------------
Now let's make a table of the values we just found.
Table of Values:
Now let's plot the points:
Graph:
Now draw a curve through all of the points to graph  :
 Graph of
================================================================
# 2
In order to graph  , we need to plot a few points.
 Start with the given equation.
 Plug in  (note: you can start at any x-value).
 Add.
 Raise 4 to the -2nd power to get  .
So when  ,  . So we have the point (-4,0.063).
----------------------------
 Start with the given equation.
 Plug in  .
 Add.
 Raise 4 to the -1st power to get  .
So when  ,  . So we have the point (-3,0.25).
----------------------------
 Start with the given equation.
 Plug in  .
 Add.
 Raise 4 to the 0th power to get  .
So when  ,  . So we have the point (-2,1).
----------------------------
 Start with the given equation.
 Plug in  .
 Add.
 Raise 4 to the 1st power to get  .
So when  ,  . So we have the point (-1,4).
----------------------------
Now let's make a table of the values we just found.
Table of Values:
Now let's plot the points:
Graph:
Now draw a curve through all of the points to graph  :
 Graph of
|
Rational-functions/181939: This question is from textbook Algebra2
Solve each equation by using the method for your choice. Find exact solutions.
8. x^2+8x=0
Thanks for your help! 1 solutions
Answer 136558 by jim_thompson5910(28546) on 2009-02-14 15:32:52 (Show Source):
You can put this solution on YOUR website!I'm going to use the quadratic formula:
 Start with the given equation.
 Add 0 to the left side (this does NOT change the equation)
Notice we have a quadratic equation in the form of  where  ,  , and
Let's use the quadratic formula to solve for x
 Start with the quadratic formula
 Plug in  ,  , and
 Square  to get  .
 Multiply  to get
 Subtract  from  to get
 Multiply  and  to get  .
 Take the square root of  to get  .
 or  Break up the expression.
 or  Combine like terms.
 or  Simplify.
So the answers are  or
|
Graphs/181937: draw the graph of the following linear function and give the domain and range: h(x)=-2x+3? 1 solutions
Answer 136556 by jim_thompson5910(28546) on 2009-02-14 15:05:04 (Show Source):
You can put this solution on YOUR website!
Looking at  we can see that the equation is in slope-intercept form  where the slope is  and the y-intercept is
Since  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
Also, because the slope is  , this means:
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
 So this is the graph of  through the points ) and
Now notice that the graph extends in both directions along the x-axis. So this means that ANY value of "x" can be plugged into the function.
So the domain is all real numbers.
Also, take note that the graph extends in both directions along the y-axis as well. So this tells us that the range is also ANY number.
So the range is all real numbers.
|
Quadratic_Equations/181935: the length of one leg of a right triangle is 7 meters less than the length of the other leg. the length of the hypotenuse is 13 meters. find the lengths of the legs. 1 solutions
Answer 136555 by jim_thompson5910(28546) on 2009-02-14 14:33:51 (Show Source):
You can put this solution on YOUR website!
We basically have this triangle set up:
Since the legs are  and  this means that  and
Also, since the hypotenuse is  , this means that  .
 Start with the Pythagorean theorem.
 Plug in  ,  ,
 Square  to get  .
 FOIL
 Subtract 169 from both sides.
 Combine like terms.
Notice we have a quadratic equation in the form of  where  ,  , and
Let's use the quadratic formula to solve for x
 Start with the quadratic formula
 Plug in  ,  , and
 Negate  to get  .
 Square  to get  .
 Multiply  to get
 Rewrite  as
 Add  to  to get
 Multiply  and  to get  .
 Take the square root of  to get  .
 or  Break up the expression.
 or  Combine like terms.
 or  Simplify.
So the possible answers are  or
However, a negative length is NOT possible. So  is NOT a solution
So the only answer is
================================================================
Answer:
So the solution is
This means that the other leg is
So the two legs are: 12 and 5 units
|
Polynomials-and-rational-expressions/181934: These need to be factored completely
30z^8 + 44z^5 +16z^2 Could it be 2z^2(3z^ + 2)(5z^3 +4)
24x² + 14xy +2y²
(m+n)(x+3) + (m+n)(5+5) Could it be (m+n+3)(x+y+5)
Solve using the principal of zero products
(x+ 1/7)(x-4/5) = 0
Find the x-intercepts for the graph of the equation
Y = x² + 4x -45 Could it be (-9,0,(5,0)
Factor by grouping
-36x² -30x + 36 Could it be -6(3x-2)(2x+3)
1 solutions
Answer 136554 by jim_thompson5910(28546) on 2009-02-14 14:25:55 (Show Source):
You can put this solution on YOUR website!I'll do the first two, which will hopefully help you with the rest of the problems. If not, then repost.
# 1
 Start with the given expression
 Factor out the GCF
Now let's focus on the inner expression
------------------------------------------------------------
Looking at  we can see that the first term is  and the last term is  where the coefficients are 15 and 8 respectively.
Now multiply the first coefficient 15 and the last coefficient 8 to get 120. Now what two numbers multiply to 120 and add to the middle coefficient 22? Let's list all of the factors of 120:
Factors of 120:
1,2,3,4,5,6,8,10,12,15,20,24,30,40,60,120
-1,-2,-3,-4,-5,-6,-8,-10,-12,-15,-20,-24,-30,-40,-60,-120 ...List the negative factors as well. This will allow us to find all possible combinations
These factors pair up and multiply to 120
1*120
2*60
3*40
4*30
5*24
6*20
8*15
10*12
(-1)*(-120)
(-2)*(-60)
(-3)*(-40)
(-4)*(-30)
(-5)*(-24)
(-6)*(-20)
(-8)*(-15)
(-10)*(-12)
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to 22? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 22
| First Number | Second Number | Sum | | 1 | 120 | 1+120=121 | | 2 | 60 | 2+60=62 | | 3 | 40 | 3+40=43 | | 4 | 30 | 4+30=34 | | 5 | 24 | 5+24=29 | | 6 | 20 | 6+20=26 | | 8 | 15 | 8+15=23 | | 10 | 12 | 10+12=22 | | -1 | -120 | -1+(-120)=-121 | | -2 | -60 | -2+(-60)=-62 | | -3 | -40 | -3+(-40)=-43 | | -4 | -30 | -4+(-30)=-34 | | -5 | -24 | -5+(-24)=-29 | | -6 | -20 | -6+(-20)=-26 | | -8 | -15 | -8+(-15)=-23 | | -10 | -12 | -10+(-12)=-22 |
From this list we can see that 10 and 12 add up to 22 and multiply to 120
Now looking at the expression  , replace  with  (notice  adds up to  . So it is equivalent to  )
Now let's factor  by grouping:
 Group like terms
 Factor out the GCF of  out of the first group. Factor out the GCF of  out of the second group
 Since we have a common term of  , we can combine like terms
So  factors to
So this also means that  factors to  (since  is equivalent to  )
------------------------------------------------------------
So our expression goes from  and factors further to
------------------
Answer:
So  completely factors to
# 2
 Start with the given expression
 Factor out the GCF
Now let's focus on the inner expression
------------------------------------------------------------
Looking at  we can see that the first term is  and the last term is  where the coefficients are 12 and 1 respectively.
Now multiply the first coefficient 12 and the last coefficient 1 to get 12. Now what two numbers multiply to 12 and add to the middle coefficient 7? Let's list all of the factors of 12:
Factors of 12:
1,2,3,4,6,12
-1,-2,-3,-4,-6,-12 ...List the negative factors as well. This will allow us to find all possible combinations
These factors pair up and multiply to 12
1*12
2*6
3*4
(-1)*(-12)
(-2)*(-6)
(-3)*(-4)
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to 7? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 7
| First Number | Second Number | Sum | | 1 | 12 | 1+12=13 | | 2 | 6 | 2+6=8 | | 3 | 4 | 3+4=7 | | -1 | -12 | -1+(-12)=-13 | | -2 | -6 | -2+(-6)=-8 | | -3 | -4 | -3+(-4)=-7 |
From this list we can see that 3 and 4 add up to 7 and multiply to 12
Now looking at the expression  , replace  with  (notice  adds up to  . So it is equivalent to  )
Now let's factor  by grouping:
 Group like terms
 Factor out the GCF of  out of the first group. Factor out the GCF of  out of the second group
 Since we have a common term of  , we can combine like terms
So  factors to
So this also means that  factors to  (since  is equivalent to  )
------------------------------------------------------------
So our expression goes from  and factors further to
------------------
Answer:
So  completely factors to
|
Miscellaneous_Word_Problems/181933: 25 + (x-1)^2 = C^2
this is the formula i came up with from the word question:
A ladder is leaning against a building so that the distance from the ground to the top of the ladder in one foot less than the length of the ladder. Find the length of the ladder if the distance from the bottom of the ladder to the building is 5 feet. 1 solutions
Answer 136553 by jim_thompson5910(28546) on 2009-02-14 14:17:02 (Show Source):
You can put this solution on YOUR website!Let x=length of ladder
Since "the distance from the ground to the top of the ladder in one foot less than the length of the ladder.", this means that one leg of the triangle is  ft. Also, we're given the other leg of 5 ft.
So this tells us that  ,  and
 Start with Pythagorean's Theorem
 Plug in  ,  and
 Square 5 to get 25
 FOIL
 Subtract  from both sides.
 Combine like terms.
 Subtract  from both sides.
 Combine like terms on the right side.
 Divide both sides by  to isolate  .
 Reduce.
----------------------------------------------------------------------
Answer:
So the answer is
So this means that the length of the ladder is 13 ft while the height that the ladder reaches on the building is 12 ft.
|
Graphs/181883: The line through (2,-3) that is perpendicular to the line y= -4x + 8 written in standard form containing only integer coefficients. I am having a horrible time with these graphs, any help is greatly appreciated! 1 solutions
Answer 136508 by jim_thompson5910(28546) on 2009-02-13 23:38:02 (Show Source):
You can put this solution on YOUR website!
We can see that the equation  has a slope  and a y-intercept  .
Now to find the slope of the perpendicular line, simply flip the slope  to get  . Now change the sign to get  . So the perpendicular slope is  .
Now let's use the point slope formula to find the equation of the perpendicular line by plugging in the slope  and the coordinates of the given point ) .
 Start with the point slope formula
 Plug in  ,  , and
 Rewrite  as
 Multiply both sides by 4.
 Distribute
 Subtract 12 from both sides.
 Subtract "x" from both sides.
 Combine like terms.
 Rearrange the terms.
 Multiply EVERY term by -1 to make the "x" coefficient positive.
=============================================
Answer:
So the equation of the line that is perpendicular to  and goes through the point (2,-3) in standard form is
Here's the graph of the two lines to verify the answer:
 Graph of the original equation  (red) and the perpendicular line  (green) through the point ) .
|
Graphs/181882: The line through (-2,-1) that is parallel to the line 5x + 3y =9. I am having a horrible time trying to write solve this and then write it into standard form containing only integer coefficients. 1 solutions
Answer 136507 by jim_thompson5910(28546) on 2009-02-13 23:12:05 (Show Source):
You can put this solution on YOUR website!
 Start with the given equation.
 Rearrange the terms.
 Divide both sides by  to isolate y.
 Break up the fraction.
 Reduce.
We can see that the equation  has a slope  and a y-intercept  .
Since parallel lines have equal slopes, this means that we know that the slope of the unknown parallel line is  .
Now let's use the point slope formula to find the equation of the parallel line by plugging in the slope  and the coordinates of the given point ) .
 Start with the point slope formula
 Plug in  ,  , and
 Rewrite  as
 Rewrite  as
 Multiply both sides by 3.
 Distribute
 Add 5x to both sides.
 Subtract 3 from both sides.
 Combine and rearrange the terms.
=======================================
Answer:
So the equation of the line that is parallel to  and that goes through (-2,-1) is:
Also, the equation is in standard form  where  ,  , and
|
Expressions-with-variables/181876: I have tried this but I am having trouble, can you please help. Use substitution to solve each system. If it does not have one solution then put no solution or indinitely many solutions. X-5Y=36 2X+Y=-16 1 solutions
Answer 136492 by jim_thompson5910(28546) on 2009-02-13 20:20:35 (Show Source):
You can put this solution on YOUR website!
Start with the given system of equations:
Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to solve for y.
So let's isolate y in the second equation
 Start with the second equation
 Subtract  from both sides
 Rearrange the equation
---------------------
Since  , we can now replace each  in the second equation with  to solve for
 Plug in  into the first equation. In other words, replace each  with  . Notice we've eliminated the  variables. So we now have a simple equation with one unknown.
 Distribute  to
 Multiply
 Combine like terms on the left side
 Subtract 80 from both sides
 Combine like terms on the right side
 Divide both sides by 11 to isolate x
 Divide
-----------------First Answer------------------------------
So the first part of our answer is:
Since we know that  we can plug it into the equation  (remember we previously solved for  in the first equation).
 Start with the equation where  was previously isolated.
 Plug in
 Multiply
 Combine like terms
-----------------Second Answer------------------------------
So the second part of our answer is:
-----------------Summary------------------------------
So our answers are:
 and
which form the point
Now let's graph the two equations (if you need help with graphing, check out this solver)
From the graph, we can see that the two equations intersect at ) . This visually verifies our answer.
 graph of  (red) and  (green) and the intersection of the lines (blue circle).
|
Expressions-with-variables/181877: I have tried this but I am having trouble, can you please help. Use substitution to solve each system. If it does not have one solution then put no solution or indinitely many solutions. 4X-5Y=-7 Y=5X 1 solutions
Answer 136491 by jim_thompson5910(28546) on 2009-02-13 20:17:28 (Show Source):
You can put this solution on YOUR website!
Start with the given system
 Plug in  into the first equation. In other words, replace each  with  . Notice we've eliminated the  variables. So we now have a simple equation with one unknown.
 Distribute
 Combine like terms on the left side
 Divide both sides by -21 to isolate x
 Reduce
Now that we know that  , we can plug this into  to find
 Substitute  for each
 Multiply
So our answer is  and  which also looks like
|
Polynomials-and-rational-expressions/181869: Factor completely and show steps:
x^2-5x-14 1 solutions
Answer 136489 by jim_thompson5910(28546) on 2009-02-13 20:11:25 (Show Source):
You can put this solution on YOUR website!
Looking at the expression  , we can see that the first coefficient is  , the second coefficient is  , and the last term is  .
Now multiply the first coefficient  by the last term  to get  .
Now the question is: what two whole numbers multiply to  (the previous product) and add to the second coefficient  ?
To find these two numbers, we need to list all of the factors of  (the previous product).
Factors of  :
1,2,7,14
-1,-2,-7,-14
Note: list the negative of each factor. This will allow us to find all possible combinations.
These factors pair up and multiply to  .
1*(-14)
2*(-7)
(-1)*(14)
(-2)*(7)
Now let's add up each pair of factors to see if one pair adds to the middle coefficient  :
| First Number | Second Number | Sum | | 1 | -14 | 1+(-14)=-13 | | 2 | -7 | 2+(-7)=-5 | | -1 | 14 | -1+14=13 | | -2 | 7 | -2+7=5 |
From the table, we can see that the two numbers  and  add to  (the middle coefficient).
So the two numbers  and  both multiply to and add to
Now replace the middle term  with  . Remember,  and  add to  . So this shows us that  .
 Replace the second term  with  .
 Group the terms into two pairs.
 Factor out the GCF  from the first group.
 Factor out  from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.
 Combine like terms. Or factor out the common term
---------------------------------------------
Answer:
So  factors to  .
Note: you can check the answer by FOILing  to get  or by graphing the original expression and the answer (the two graphs should be identical).
|
Polynomials-and-rational-expressions/181871: Factor completely and show steps:
6x^2-13x-5
1 solutions
Answer 136488 by jim_thompson5910(28546) on 2009-02-13 20:10:38 (Show Source):
You can put this solution on YOUR website!
Looking at the expression  , we can see that the first coefficient is  , the second coefficient is  , and the last term is  .
Now multiply the first coefficient  by the last term  to get  .
Now the question is: what two whole numbers multiply to  (the previous product) and add to the second coefficient  ?
To find these two numbers, we need to list all of the factors of  (the previous product).
Factors of  :
1,2,3,5,6,10,15,30
-1,-2,-3,-5,-6,-10,-15,-30
Note: list the negative of each factor. This will allow us to find all possible combinations.
These factors pair up and multiply to  .
1*(-30)
2*(-15)
3*(-10)
5*(-6)
(-1)*(30)
(-2)*(15)
(-3)*(10)
(-5)*(6)
Now let's add up each pair of factors to see if one pair adds to the middle coefficient  :
| First Number | Second Number | Sum | | 1 | -30 | 1+(-30)=-29 | | 2 | -15 | 2+(-15)=-13 | | 3 | -10 | 3+(-10)=-7 | | 5 | -6 | 5+(-6)=-1 | | -1 | 30 | -1+30=29 | | -2 | 15 | -2+15=13 | | -3 | 10 | -3+10=7 | | -5 | 6 | -5+6=1 |
From the table, we can see that the two numbers  and  add to  (the middle coefficient).
So the two numbers  and  both multiply to and add to
Now replace the middle term  with  . Remember,  and  add to  . So this shows us that  .
 Replace the second term  with  .
 Group the terms into two pairs.
 Factor out the GCF  from the first group.
 Factor out  from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.
 Combine like terms. Or factor out the common term
---------------------------------------------
Answer:
So  factors to  .
Note: you can check the answer by FOILing  to get  or by graphing the original expression and the answer (the two graphs should be identical).
|
Quadratic_Equations/181829: Method of Substitution
1. Solve each linear system using the method of substitution. Check your answers.
a) y=3x-4
x+y=8
Pleaseeeee and thank you very much i need it right now pleasee 1 solutions
Answer 136421 by jim_thompson5910(28546) on 2009-02-13 13:47:07 (Show Source):
You can put this solution on YOUR website! Start with the second equation
 Plug in  . In other words, replace every "y" with 3x-4
 Combine like terms
 Add 4 to both sides
 Divide both sides by 4 to isolate "x"
So the first part of the answer is
 Go back to the first equation
 Plug in
 Multiply
 Subtract
So the second part of the answer is
=========================================
Answer:
So the solutions are  and  which form the ordered pair (3,5)
I'll let you do the check (simply plug in the two solutions and simplify)
|
Graphs/181828: Find the slope and y-intercept of the line y = 3x + 4
I tried so hard I just can't get it. 1 solutions
Answer 136420 by jim_thompson5910(28546) on 2009-02-13 13:41:52 (Show Source):
You can put this solution on YOUR website!Notice how the line is of the form  where "m" is the slope and "b" is the y-intercept.
So this simply means that  and  which tells us that the slope is 3 and the y-intercept is 4
|
Graphs/181816: This question is from textbook Elementary and Intermediate
The Addition Method x-2y=-1 Solve system by addition
-x+5y=4 1 solutions
Answer 136414 by jim_thompson5910(28546) on 2009-02-13 13:27:02 (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


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 1 and -1 to some equal number, we could try to get them to the LCM.
Since the LCM of 1 and -1 is -1, we need to multiply both sides of the top equation by -1 and multiply both sides of the bottom equation by -1 like this:
Multiply the top equation (both sides) by -1
Multiply the bottom equation (both sides) by -1
So after multiplying we get this:


Notice how -1 and 1 add to zero (ie )
Now add the equations together. In order to add 2 equations, group like terms and combine them


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:

Divide both sides by to solve for y
Reduce
Now plug this answer into the top equation to solve for x
Plug in 
Multiply
Subtract from both sides
Combine the terms on the right side
Multiply both sides by . This will cancel out on the left side.
Multiply the terms on the right side
So our answer is
, 
which also looks like
( , )
Notice if we graph the equations (if you need help with graphing, check out this solver)


we get
graph of (red) (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 ( , ). This verifies our answer. |
|
|