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

 Tutoring Home For Students Tools for Tutors Our Tutors Register Recently Solved
 By Tutor
| By Problem Number |

Tutor:

# Recent problems solved by 'Earlsdon'

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, >>Next

 Quadratic_Equations/23275: Maximum profit using the quadratic equations, functions, inequalities and their graphs. A chain store manager has been told by the main office that daily profit, P, is related to the number of clerks working that day, x, according to the equations P = -25x^2 + 300x. What number of clerks will maximize the profit, and what is the maximum possible profit?1 solutions Answer 12018 by Earlsdon(6287)   on 2005-12-31 11:29:27 (Show Source): You can put this solution on YOUR website!Maximise: This is the equation of a parabola that opens downwards (coefficient of x^2 is negative) so the maximum value of P (the dependent variable) will be found at the parabola's vertex. The x-coordinate of the vertex is given by: and so the maximum value of P will be found at Your equation is already in the standard form: (a = -25, b = 300, c = 0) so we can find the x-coordinate at which P will be the maximum. Simplify. To maximise profits, the manager should employ 6 clerks. The maximum profit can be found by substituting 6 for x in the original equation for P. Maximum profit is 900 (dollars ?)
 Quadratic_Equations/23274: Maximum cost using the quadratic equations, functions, inequalities and their graphs. It costs Acme Manufacturing C dollars per hour to operate its golf ball division. An analyst has determined that C is related to the number of golf balls produced per hour, x, by the equation C = 0.009x^2 - 1.8x + 100. What number of balls per hour should Acme produce to minimize the cost per hour of manufacturing these golf balls?1 solutions Answer 12017 by Earlsdon(6287)   on 2005-12-31 10:55:52 (Show Source): You can put this solution on YOUR website!Minimise: This is the equation of a parabola that opens upwards (Coefficient of x^2 is positive), so the minimum value of C would be at the parabola's vertex. The x-coordintate of the vertex is given by: Your equation is already in standard form: so here: a = .009 and b = -1.8. The minimum value of C will be found at Simplify. Acme should produce 100 ball per hour to minimise the cost per hour. It might be helpful to see the graph of the cost, C (vertical axis) versus x (horizontal axis) the number of balls produced:
 Exponents/22544: In a pattern the number of colored tiles used in row x is 3 with an exponent of x. How many tiles are used in rows 4, 5, and 6 of the pattern?1 solutions Answer 11690 by Earlsdon(6287)   on 2005-12-27 11:20:40 (Show Source): You can put this solution on YOUR website!If row x has tiles, then: row 4 has tiles. row 5 has tiles. row 6 has...well, you get the idea by now.
 Percentage-and-ratio-word-problems/22530: the amount of water a pipe can allow to flow varies directly as the time it is open. If 350 gallons flow through in 20 minutes, how many hours will it takt to get 3000 gallons of water?1 solutions Answer 11575 by Earlsdon(6287)   on 2005-12-22 21:26:58 (Show Source): You can put this solution on YOUR website!First set up the equation of proportionality: Let F = flow in gallons and T = time in hours. where k is the constant of proportionality. Solve for k. Substitute F = 350 gallons and T = 20 mins = 1/3 hour. Now you can solve the problem: Substitute F = 3000 gallons and k = 1050 hrs T = 2 hrs. 51 mins. 25.2 secs.
 Percentage-and-ratio-word-problems/23068: Please help. I'm trying to assist my friend's daughter and I'm very rusty. A river is 3,100 meters wide There is a bridge that spans the river 1/10 of the bridge lies on one side of the river 1/8 of the bridge lies on the other side of the river How long is the bridge 1 solutions Answer 11505 by Earlsdon(6287)   on 2005-12-21 11:10:47 (Show Source): You can put this solution on YOUR website!Try some WD-40 for your rust problem. (lol) The bridge is 3,100m + (1/10)(3,100m) + (1/8)(3,100m) = 3,100 + 310 + 387.5 = 3797.5 meters long.
 Proportions/22864: This is Tim Hunt again. I am confused about one of the questions you helped me with. 1 tablespoonful qid (four times a day) for 3 days (4 X 3) = 12 tablespoonsful. 1 Tablespoonful = 15 ml approximately. Perhaps your PDR has the exact conversion factor for this but I think it's more like 14.7868 ml per tbsp. 12 tbsp = 180 ml approximately. 12 tbsp = 177.4412 ml more precisely. How did you get 14.7868 I know 12 x 15 = 180 and how did you get 177.4412? Please help 1 solutions Answer 11467 by Earlsdon(6287)   on 2005-12-20 21:29:50 (Show Source): You can put this solution on YOUR website!I was trying to use a more precise conversion factor by using 14.7868 ml per tablespoon. If 1 tablespoon = 14.7868 ml, then 12 tablespoons = 12(14.7868) = 177.4416 ml If you are allowed to use the approximate conversion factor of 1 tablespoon = 15 ml, I would go with that. So 12 tablespoons = 12(15) = 180 ml.
 Equations/22886: Please Help me solve this equation: simplify each: y^-7 Thanks !1 solutions Answer 11465 by Earlsdon(6287)   on 2005-12-20 21:18:12 (Show Source): You can put this solution on YOUR website!First, a quick clarification. You have an expression not an equation. An equation is some equal to something else and you will see the = sign in an equation. An expression has no = sign. Simplify: Remember that: , so:
 Exponential-and-logarithmic-functions/22916: I'm having trouble with this text book question can you show me how to solve it graph parabola with vertex and intercepts f(X)= xsquared+6X+5 (sorry I dont know how to make a small 2 after the first x)1 solutions Answer 11463 by Earlsdon(6287)   on 2005-12-20 21:12:40 (Show Source): You can put this solution on YOUR website!Ok, you can show x squared like this...x^2 by using the caret (^). You get the caret by Shift-6 key. A little advice...use the same type letter (all upper case or all lower case) for the variable in your problems, rather than swithichjng from X to x and back again. Solve: You can also write your equation: You can solve this by factoring if you set y = 0 Apply the zero product principle. and/or If then, If then, The x-intercepts (also called zeros) are: The x-coordinate of the vertex is found by: The a and b come from the standard form of the quadratic equation: In your equation, a = 1 and b = 6 This the x-coordinate of the vertex. Find the y-coordinate by substituting this value of x into your equation and solving for y. x = -3 The vertex is at (-3, -4) Here's the graph.
 Exponents/23051: Does (2a)^2 (or 2a*2a) = 4a^2? Thanks!1 solutions Answer 11460 by Earlsdon(6287)   on 2005-12-20 20:50:29 (Show Source): You can put this solution on YOUR website!Yes! =
 Graphs/23038: write an equation in point slope form that passes through (8,-2)and is parellel to the graph of y= 2x-4.1 solutions Answer 11449 by Earlsdon(6287)   on 2005-12-20 16:58:09 (Show Source): You can put this solution on YOUR website!Recall that the point=slope form is: y = mx + b You can find the slope of the new line when you remember that parallel lines have the same slope. The slope of the given line is easily seen when you compare the given equation with the general slope-intercept form. y = 2x - 4 compare with: y = mx + b and you can see that the slope of the given line, and of any line parallel to it, is m = 2 So you can start your new equation off with: y = 2x + b Now, since this line passes through the point (8, -2), then the coordintates of the point (x = 8 and y = -2) must satisfy this equation. Substitute these values of x and y into you new equation: -2 = 2(8) + b now you can solve this for b. -2 = 16 + b Subtract 16 from both sides of the equation. -18 = b Now you can write your final equation: y = 2x - 18
 Linear-equations/22991: Is it possible that someone could teach me everything about Linear Equations..the steps are so confusing. I just need help BAD!1 solutions Answer 11402 by Earlsdon(6287)   on 2005-12-19 22:00:31 (Show Source): You can put this solution on YOUR website!I expect it is possible that you can find a tutor here. I would also suggest that you check with school and ask about math tutoring. Most schools will provide their students with a tutor upon request or, if they can't, they can most-likely refer you to a local tutor. The bottom line is that you need to get one-on-one tutoring in this subject if you so desperately need help.
 Coordinate-system/22999: what is the definition of a preimage?1 solutions Answer 11401 by Earlsdon(6287)   on 2005-12-19 21:54:26 (Show Source): You can put this solution on YOUR website!"Pre" means before so "Preimage" means the image before the tranformation. In other words...the "before" picture in "Before-and-after"
 Polynomials-and-rational-expressions/22872: Help!!!! Completely factor the polynomial X^3+2X^2-120X. Thanks very much1 solutions Answer 11309 by Earlsdon(6287)   on 2005-12-18 21:06:56 (Show Source): You can put this solution on YOUR website!Factor completely: First, factor an x. Now factor the parentheses. Done!
 Permutations/22918: I am learning counting in Algebra and Geometry and I am doing review for my test tmr. There's one question I can not do or understand in the review: A cable contains 12 wires that are colour coded. There are 3 green, 3 red, 3 black, and 3 white wires. How many subsets of four wires can be seleted if there are no restrictions? Note: Order does matter! (Answer: 495) Can you list out all the possible cases and show me how you calculate it. Thanks Here's what I got (please tell me what I am doing wrong): Case #1, all 4 wires are different (3C1)^4 = 81 (Note 3C1 is 3 choose 1) Case #2, 2 wires are the same colour, the other 2 is different (i.e. ggrb, rrgb etc) 4C3 * 4! / 2! = 48 Case #3, 2 pairs of the same colour (i.e. ggww, bbrr, etc.) 4C2 * 4! / 2! / 2! = 36 Case #4, 3 wires are same color and the other one is different (i.e. gggw, etc) 4C2 * 4! / 3! = 241 solutions Answer 11308 by Earlsdon(6287)   on 2005-12-18 20:40:39 (Show Source): You can put this solution on YOUR website!This is a "combinations" (order doesn't matter) problem in which you want to know the number of combinations of 12 things taken 4 at a time. The left side is Combination of 12 things taken 4 at a time.
 Rational-functions/22914: I was told to solve by factoring. 4x^3-28x^2+49x>0 I thought that with factoring you have to have x2 x and a number. For some reason my mind is going blank. Please help if you can.1 solutions Answer 11306 by Earlsdon(6287)   on 2005-12-18 20:22:43 (Show Source): You can put this solution on YOUR website!Factor: First, factor out an x Now factor the parentheses. Does this help?
 Exponential-and-logarithmic-functions/22939: I have a home work problem that I have to solve factor but I don't think it is factorable is ther an alternate way to solve it or is the answer itisn't factorable. X^2+4X+2=0 (X+ )(X+ )1 solutions Answer 11305 by Earlsdon(6287)   on 2005-12-18 20:05:52 (Show Source): You can put this solution on YOUR website!Yes there is. Quadratic equations are always solvable by using the quadratic formula: For your equation, this would look like: The roots are:
 Exponential-and-logarithmic-functions/22924: I was wondering if anyone could help me solve this homework problem x^2 = 2x + 151 solutions Answer 11293 by Earlsdon(6287)   on 2005-12-18 18:22:17 (Show Source): You can put this solution on YOUR website!First, rewrite your equation in standard form: becomes: Solve by factoring. Now apply the zero product principle. and/or If then, If then, The roots are: x = -3 x = 5
 logarithm/22906: I'm having trouble with this text book question can you show me how to solve it log(3x-7)=211 solutions Answer 11286 by Earlsdon(6287)   on 2005-12-18 10:51:12 (Show Source): You can put this solution on YOUR website!Recall that: means: Applying this to your problem: means: Add 7 to both sides. Finally, divide both sides by 3.
 Coordinate-system/22853: how do you find the values for m and b in the following systems so that the solutions to the system is (-3,4) 5x+ 7y=b and mx+y=221 solutions Answer 11246 by Earlsdon(6287)   on 2005-12-17 11:28:28 (Show Source): You can put this solution on YOUR website!Simply substitute the given values of x and y (-3, 4) into the two equations and solve for the respective values of b and m. 1) 5x + 7y = b Substitute x = -3 and y = 4. 5(-3) + 7(4) = b Simplify. -15 + 28 = b b = 13 2) mx + y = 22 Substitute x = -3 and y = 4. m(-3) + 4 = 22 Subtract 4 from both sides of the equation. -3m = 18 Finally, divide both sides of the equation by -3. m = -6
 Graphs/22855: can u tell me how to find the slope of the line whose equation is given: y = 3x + 2 (without using a graph to get the answer)1 solutions Answer 11244 by Earlsdon(6287)   on 2005-12-17 11:21:04 (Show Source): You can put this solution on YOUR website!Yes! Note that the given equation is already in the slope-intercept form: y = mx + b where: m = the slope and b = the y-intercept. Compare this with the given equation. y = 3x + 2 and you can easily see that m = 3 so the slope of your line is 3.
 Proportions/22856: Hello, My ame is Delores Pack I'm not that good in math, so I came to place that probably can help me. I'm struggling, and getting stressed out. 1. How many 0.0125 grain doses can be made from 3/8 grains of a drug? 2. A formula for 1000 tablets contains 11.5 grams of an antihistamine. How many grams of the antihistamine should be used to prepare 475 tablets? 3. If a syringe contains 28 mg of drug in 3 ml how many milligrams of the drug would a patient receive if 1.2 ml is administered? 1 solutions Answer 11243 by Earlsdon(6287)   on 2005-12-17 11:16:33 (Show Source): You can put this solution on YOUR website!1) First convert 3/8 to a decimal. Just divide 3 by 8 to get 0.375. Next, you need to find out how many times does 0.0125 go into 0.375, so this is a division problem. Answer: You can get thirty 0.0125-grain doses from 3/8 grains of a drug. 2) If 1000 tablets contain 11.5 grams of an antihistamine, you need to find out how much antihistamine 1 tablet contains. Do it like this: (1000 tablets)/1000 = 11.5 grams/1000 1 tablet = 0.0115 grams Now, to find out how much antihistamine is in 475 tablets, do it like this: 1 tablet = 0.0115 grams 475 (1 tablet) = 475(0.0115) grams 475 tablets = 5.4625 grams of antihistamine. 3) You can use proportions on this problem. Solve for x. Multiply both sides of the equation by 1.2ml Do the math. Answer: The patient would receive 11.2 mg of the drug.