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# Recent problems solved by 'Earlsdon'

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 Miscellaneous_Word_Problems/385992: I hope I got the right section. I'm having trouble with "Chemical Word Problems" (that's what my textbook says). The original problem is "One solution was 5% bromide,, and the other was 40% bromide. How much of each should be used to get 60 milliliters of a solution that is 12% bromide?" The 5% bromide "container" I labelled N. The 40% I labelled D (per the instructions of my text). What I did: I realized that I have two equations: N+d=100 (according to the textbook)which means that n= 100-d ; So I wrote this: ( ) + ( ) = 100 I plugged "n" into the first paranthes, and d into the second. I turned the percents into decimals (5%= 0.5 and 40%= 0.4). I plugged it in, to get: 0.5(N) + 0.4(D) = (100)0.12 (0.12=12%) Since N=100-D, I replaced N with 100-D to get: 0.5(100-D) + 0.4D = 12 I solved to get 50 - 0.5D + 0.4D = 12 --> 50 - .1D =12 ------> Subtracted 50 from both sides to get ----->-.1DN= -38 ----> divided both sides by -.1 ----> and I got 380. Logically, that can't be, because N+D=100. If D = 380 which is greater than 100... What am I doing wrong?!? I've done other problems of this nature, using the SAME process, and they have all been wrong! Please Help!1 solutions Answer 272957 by Earlsdon(6287)   on 2010-12-14 11:37:45 (Show Source): You can put this solution on YOUR website!Try this! Let x = the required number of ml. of the 5% bromide solution. Then (60-x) will be the required number of ml. of the 40% bromide solution and the sum of these two amounts (x+60-x) will equal the 60 ml. of the final 12% bromide solution. Here's the equation after changing the percentages to their decimal equivalents: 0.05x+0.4(60-x) = 0.12(60) Simplify and solve for x. 0.05x+24-0.4x = 7.2 Combine like-terms. 0.05x-0.4x+24 = 7.2 -0.35x+24 = 7.2 Subtract 24 from both sides. -0.35x = -16.8 Divide both sides by -0.35 x = 48 and 60-x = 12 So you'll need to mix 48 ml. of 5% bromide solution with 12 ml. of 40% bromide solution to obtain 60 ml. of 12% bromide solution.
 Age_Word_Problems/385025: I need help with this math problem. x-1 under the square root+x=71 solutions Answer 272496 by Earlsdon(6287)   on 2010-12-12 18:18:17 (Show Source): You can put this solution on YOUR website!Solve for x??? Subtract x from both sides. Square both sides. Add 1 to both sides. Subtract x from both sides. Rearrange into standard form. Factor. Apply the zero product rule. or so... or
 Square-cubic-other-roots/385050: Solve for x: √(x+7)=x-51 solutions Answer 272494 by Earlsdon(6287)   on 2010-12-12 18:07:05 (Show Source): You can put this solution on YOUR website!Solve for x: Square both sides. Simplify. Subtract x from both sides. Subtract 7 from both sides. Factor. Apply the zero product rule. or so... or
 test/384758: I am asking this question again because I am just not sure I got it! line passing thru (3,0) and (-1,-2) slope:1/2 so what is the equation of the line in y=mx+b form1 solutions Answer 272382 by Earlsdon(6287)   on 2010-12-12 11:19:08 (Show Source): You can put this solution on YOUR website!The equation of the line passing through the points: (3, 0) and (-1, -2) and having a slope of in slope-intercept form: where the slope . Start with: since you were given the slope, m. To find the value of b, the y-intercept, substitute the x- and y-coordinates from either one of the two given points. Let's choose (3, 0) Substitute x = 3 and y = 0. Simplify. Subtract from both sides. Now substitute this into the equation above to get:
 logarithm/384763: Simplify the following expression. Your answer should not contain logarithms. e^(ln30x^5-ln6x^4)1 solutions Answer 272381 by Earlsdon(6287)   on 2010-12-12 11:10:16 (Show Source): You can put this solution on YOUR website!Simplify: Simplify the exponent using the quotient rule: e^(ln(30x^5/6x^4)) Simplify the argument of the ln in the exponent. Recall that: so...
 test/384757: I asked this question yesterday- but forgot a negative sign, which I do not know what to do with.... (x^9y^-6)^1/31 solutions Answer 272378 by Earlsdon(6287)   on 2010-12-12 10:54:45 (Show Source): You can put this solution on YOUR website!I presume that you want to simplify this expression! Remember that: so... Multiply the exponents inside the parentheses by the exponent on the outside to get:
 Polynomials-and-rational-expressions/384605: I am having a nightmare with this one. Can someone please help me. A 75-ft diagonal brace on a bridge connects a support of the center of the bridge to a side support on the bridge. The horizontal distance that it spans is 15 ft longer that the height that it reaches on the side of the bridge. Find the horizontal and vertical distances spanned by this brace. 1 solutions Answer 272259 by Earlsdon(6287)   on 2010-12-11 21:08:31 (Show Source): You can put this solution on YOUR website!You could use the Pythagorean theorem to solve this problem. You have a right triangle whose hypotenuse is the 75ft. diagonal and whose height is h. The base of this triangle is h+15ft. You need to find h and h+15. Rewrite as a quadratic equation in standard form. Divide by 2 to simplify a bit. Solve by factoring. Apply the zero product rule. or or Discard the negative solution as the height, h, is a positive quantity. feet. This is the vertical distance. feet. This is the horizontal distance. ----------------------------------------------------- I do hope this takes care of your nightmare! -----------------------------------------------------
 Linear_Equations_And_Systems_Word_Problems/384103: Another word problem that has stumped me. You recently started the paperwork to purchase your new home, and were just notified that you can move into the house in 2 weeks. You decide to hire a moving company, but are unsure which company to choose. You search online and are interested in contacting two companies. Heavy lifting and quick move, to discuss their rates. Heavy lifing chrges an \$80 fee plus \$35 per hour. Quick Move charges \$55 per hour with no additonal fees. A. which mover provides a better deal for 2 hours of work? How did I arrive at my answer. (clueless) B. Which mover provided a better deal for 15 hour of work? How did I arrive at that answer? C. For what values H(hours) does quick Move offer the better deal? Express my answer as an Inequality. Explain hou I reach that answer. I seem to get mixed up on how to use the right formulas. can you explain each step so I can understand how to do this!1 solutions Answer 271935 by Earlsdon(6287)   on 2010-12-10 11:07:28 (Show Source): You can put this solution on YOUR website!Start by assigning a letter to represent the unknown quantity. Let H = the number of hours. Now write the two equations for the total cost of of the move by each of the two movers. HL = Heavy lifting and QM = Quick move.. HL = 35H+80 QM = 55H A) Let H = 2 hours. HL = 35(2)+80 HL = 70+80 HL = \$150 QM = 55(2) QM = \$110 Quick moves is the better choice for 2 hours work. B) Let H = 15 hours. HL = 35(15)+80 You can work this out. QM = 55(15) This one too. The smallest answer wins. C) Here you need to find the value of H in the inequality: QM < HL so... 55H < 35H+80 Solve fo H. Subtract 35H from both sides. 20H < 80 Divide both sides by 20. H < 4 hours Quick move is the better deal for moves less than 4 hours.
 Exponential-and-logarithmic-functions/383530: 8^2x-1=90 I need this to the nearest thousandths1 solutions Answer 271572 by Earlsdon(6287)   on 2010-12-09 09:17:53 (Show Source): You can put this solution on YOUR website!Solve for x, to the nearest thousandth. Is this right? Take the log of both sides. Apply the power rule to the left side. Divide both sides by Evaluate the right side. Divide both sides by 2.
 Polynomials-and-rational-expressions/383528: What are you really solving for when solving quadratic equations?1 solutions Answer 271566 by Earlsdon(6287)   on 2010-12-09 09:09:03 (Show Source): You can put this solution on YOUR website!You are solving for the coordinates on the x-axis where the parabola (the graph of a quadratic equation) intersects the x-axis, if it does intersect it. You will usually have two different values of x but not always. If the parabola just touches the x-axis, then you will have a "double" solution in which the two values of the x-coordinate are identical. If the parabola does not intersect the x-axis, then the solution to the quadratic equation will not be "real" numbers but "complex" numbers of the form
 logarithm/382926: find an approximate solution to 2^x=31 solutions Answer 271267 by Earlsdon(6287)   on 2010-12-08 10:35:53 (Show Source): You can put this solution on YOUR website!Find an approximate solution: Take the log of both sides. Apply the power rule. Divide both sides by Use your calculator. Approx.
 logarithm/382936: solve for x: log x + (log x + 21)=21 solutions Answer 271266 by Earlsdon(6287)   on 2010-12-08 10:29:17 (Show Source): You can put this solution on YOUR website!Solve for x: Apply the product rule: Simplify the argument. Rewrite this in exponential form. Rewrite as a quadratic equation in standard form. Factor. Apply the zero product rule. or so... or Discard the negative solution as the log of a negative number is not real. Check: =
 Mixture_Word_Problems/381898: Hello tudor, A friend ask me this and so i started helping them. However, i got 160 lb. However, it sounded a bit weird so i want to double check. How many pounds of seed worth \$1.05 per pound must be mixed with 30 pounds of seed worth \$.90 per pound in order to produce a mixture to sell for \$1.00 per pound?1 solutions Answer 270815 by Earlsdon(6287)   on 2010-12-06 18:44:17 (Show Source): You can put this solution on YOUR website!Let x = the number of lbs of seed worth \$1.05 per pound. x(\$1.05)+30(\$0.90) = (x+30)(\$1.00) Simplify and solve for x. 1.05x+27 = x+30 Subtract x from both sides. 0.05x+27 = 30 Subtract 27 from both sides. 0.05x = 3 Finally, divide both sides by 0.05 x = 60lbs. P.S. I'm not a Tudor nor a Plantaganet.
 Miscellaneous_Word_Problems/380973: Please help me with this one, I think I have the solution but not sure. An explosion causes debris to rise vertically. The funtion f(t)=-16^2 + 72t describes the height of the debris above the ground, f(t), in feet, t seconds after the explosion. When does the debris reach its maximum height: I got (-72/-32, 81) What is the maximum height of the debris: I got (25/2, 81) When does the debris hit the ground? I got -9/2 When we do these she tells us for the first two to use b/2(a) and then then last one I did the quadratic equation. Please help me with this so I can work some more on this packet. Thank you so very much Tracy1 solutions Answer 270349 by Earlsdon(6287)   on 2010-12-05 10:30:48 (Show Source): You can put this solution on YOUR website!First, let's get the equation right! 1) The time to reach maximum height is given by: seconds. 2) The maximum height can be found by substituting the time seconds into the given equation. Substitute Evaluate. feet. 3) The time whe debris will hit the ground () can be found by setting the given equation f(t)= 0 and solving for the time, t. Factor out a t. Now apply the zero product rule: or The solution is the initial condition. Subtract 72 from both sides. Divide both sides by -16. seconds.
 test/380404: 2 pipes are connected to a tank. On pipe fills the tank in 7 hours. The second pipe empties the tank in 9 hours. If both pipes are open, how long will it take to fill the tank?1 solutions Answer 269974 by Earlsdon(6287)   on 2010-12-03 18:36:12 (Show Source): You can put this solution on YOUR website!Find the hourly rate of each event. If the first pipe can fill the tank in 7 hours, then it can fill (+) of the tank in 1 hour. If the second pipe can empty the tank in 9 hours, then it can empty (-) of the tank in 1 hour. Putting these two events together, we get: So of the tank is filled in 1 hour. It takes hours to fill the tank. hours.
 Trigonometry-basics/380408: factor: 2x^3+161 solutions Answer 269968 by Earlsdon(6287)   on 2010-12-03 18:26:56 (Show Source): You can put this solution on YOUR website!Factor: First, factor a 2. Now notice that you have the sum of two cubes in the parentheses. The sum of two cubes can be factored thus: so in this problem, A = x and B = 2.
 Radicals/380024: sqrt(x^2+2x+1)1 solutions Answer 269755 by Earlsdon(6287)   on 2010-12-02 21:45:23 (Show Source):
 Quadratic_Equations/380058: I need help! This is due tomorrow! (It's 7th grade math by the way.) The question says: Write an equation to find the value of x so that each pair of polygons has the same perimeter. Then solve. 1. A triangle has sides that say: x+6, x+9, and x+3. A rectangle beside it has sides that say x+4 and x+1. 2. A hexagon has sides that all read 5x. A triangle next to it has sides that say x+14, x+17, and 8x+9. PLEASE help me!1 solutions Answer 269753 by Earlsdon(6287)   on 2010-12-02 21:35:35 (Show Source): You can put this solution on YOUR website!1) For the triangle, let the perimeter = P, then... (x+6)+(x+9)(+x+3) = P Simplify. 3x+18 = P For the rectangle, let the perimeter = P (the same P), then... 2(x+4)+2(x+1) = P Simplify. 2x+8+2x+2 = P 4x+10 = P Now, because P = P you set these two equations equal and solve for x... 3x+18 = 4x+10 Subtract 3x from both sides. 18 = x+10 Now subtract 10 from both sides. 8 = x or x = 8. Now you can apply this to the next problem.
 Polynomials-and-rational-expressions/379744: can someone please help me i can not figure this out perform the indicated operation 12 cubed sqrt 4x - 10 cubed sqrt 4x - 6 cubed sqrt 4x your help would be greatly appreciated1 solutions Answer 269631 by Earlsdon(6287)   on 2010-12-02 14:43:37 (Show Source): You can put this solution on YOUR website!Simplify? First factor out the Now perform the indicated operations inside the parentheses. Finally, you could take the square root of 4 (that's 2) and multiply that by the 512 to get the final answer of:
 Polynomials-and-rational-expressions/379754: hi i've been working on this problem and don't know if i got the answer correct could someone please help (2x/x+12) -1 = 2/x+12 thanks1 solutions Answer 269626 by Earlsdon(6287)   on 2010-12-02 14:32:33 (Show Source): You can put this solution on YOUR website!Solve for x: Add 1 to both sides.. Subtract () from both sides. Simplify the left side. Multiply both sides by () Subtract x from both sides. Add 2 to both sides.
 Triangles/377826: All sides of a triangle are integers. If the length of 2 sides are 7 and 5, what is the largest possible perimeter? I think it is 24, but there is no answer like that in the multiple choice. The teacher might have made a mistake(she admitted it herself) but I want to be completely sure that my answer 24 is correct before telling her of her mistake. Thank you very much.1 solutions Answer 268456 by Earlsdon(6287)   on 2010-11-29 18:50:36 (Show Source): You can put this solution on YOUR website!Imagine this: If you were to lay the two given sides flat so they form a single contiguous straight line, this line would be 12 (5+7) units long. Now you could not possibly make a triangle by adding a third side of 12 units, it would have to be shorter than 12 in order to make a triangle and, since you are dealing with integral sides, the third side could be no longer than 11 units, making the maximum perimeter 7+5+11 = 23 units.
 Expressions-with-variables/377082: I need help with 382+x divided by 3=227 (382+x is all divided by 3). I know the answer is 299, but can figure out how to show it. The 299 was a guess that turned out right. Thanks, Denise1 solutions Answer 268060 by Earlsdon(6287)   on 2010-11-28 16:08:27 (Show Source): You can put this solution on YOUR website! First multiply both sides by 3. Evaluate. Subtract 382 from both sides. Evaluate.
 Percentage-and-ratio-word-problems/376445: HOw many oz. of a metal containing 66% silver must be combined with 3 oz. of a metal containing 90% sivler to form an alloy containing 85% silver?1 solutions Answer 267825 by Earlsdon(6287)   on 2010-11-27 09:31:24 (Show Source): You can put this solution on YOUR website!How much silver is there in the alloys? Let x = the number of oz of 66% silver alloy. This contains (0.66)x oz of silver. The 3 oz of 90% silver alloy contain (0.9)(3) oz of silver. The sum of these is to equal (3+x)(0.85) oz of silver. We can write the equation to solve for x. 0.66x+0.9(3) = 0.85(3+x) Simplify and solve for x. 0.66x+2.7 = 2.55+0.85x Subtract 0.66x from both sides. 2.7 = 2.55+0.19x Subtract 2.55 from both sides. 0.15 = 0.19x Finally, divide both sides by 0.19 x = 0.789 oz of the 66% silver alloy will be required.
 Functions/376055: Just need confirmation on some answers I have for this problem Find the indicated outputs for f(x) = 2 x^2-2x F (0) = I need to replace the variable x with 0. My answer is 0. f(-1) = I need to replace x with -1. My answer is 0. f(2) = Replaced with 2. My answer is 4. 1 solutions Answer 267468 by Earlsdon(6287)   on 2010-11-25 10:51:55 (Show Source): You can put this solution on YOUR website!You are correct on the first and third answers. On the second one, it goes like this: