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# Recent problems solved by 'drk'

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 Evaluation_Word_Problems/267510: p=1/3mt for m1 solutions Answer 196286 by drk(1908)   on 2010-02-09 09:49:30 (Show Source): You can put this solution on YOUR website!step 1 - multiply by 3 to get 3p = mt step 2 - divide by t to get (3p)/t = m
 Evaluation_Word_Problems/267511: A=P+PRT for T1 solutions Answer 196285 by drk(1908)   on 2010-02-09 09:48:25 (Show Source): You can put this solution on YOUR website!step 1 - subtract P to get A - P = PRT step 2 - divide by PR to get (A - P) / PR = T
 Numeric_Fractions/267496: Please help me Simplify. (1 - 16x^(2)) / (16x^(2)+8x+1)1 solutions Answer 196284 by drk(1908)   on 2010-02-09 09:47:38 (Show Source): You can put this solution on YOUR website! / factoring we get / cancel the 4x + 1 to get
 Probability-and-statistics/267508: A bag contains 6 red marbles,9 blue marbles,and 5 green marbles.you withdraw one marble,replace it'and then withdraw another marble.what is the probability that you do not pick two green marbles?1 solutions Answer 196283 by drk(1908)   on 2010-02-09 09:44:17 (Show Source): You can put this solution on YOUR website!There are 15 non green marbles. P(non green) = 15/20 P(non green and then non green) = (15/20)*(15/20) = 225/400 = 9/16
 Inverses/267506: What is the best metric unit to measure the distance between Los Angeles and New York City?1 solutions Answer 196281 by drk(1908)   on 2010-02-09 09:42:33 (Show Source): You can put this solution on YOUR website!The best metric unit is kilometers
 Square-cubic-other-roots/267505: what is the square root of 150?1 solutions Answer 196280 by drk(1908)   on 2010-02-09 09:41:46 (Show Source): You can put this solution on YOUR website!If we prime factorize 150 we get 2 x 3 x 5^2 taking out a 5, we get 5*sqrt(6) ~ 12.247
 Linear-equations/267501: Can you please explain how you find the rise, run and slope. I have to write the equation of each line in the standard form Ax+By=C, A>0. 1 solutions Answer 196279 by drk(1908)   on 2010-02-09 09:35:52 (Show Source): You can put this solution on YOUR website!here is the original equation step 1 - subtract Ax to get divide by B to get slope = -A/B y - intercept = (C/B) rise = -A and run = B
 expressions/267485: Evaluate 5r - 3s when r = 3 and s = 5.1 solutions Answer 196277 by drk(1908)   on 2010-02-09 09:23:23 (Show Source): You can put this solution on YOUR website!5*3 - 3*5 15 - 15 0
 Exponents/267388: what are six ways to solve 125^(-4/3)?1 solutions Answer 196256 by drk(1908)   on 2010-02-08 21:48:15 (Show Source): You can put this solution on YOUR website!I think I have all 6 ways: (1) --- (2) --- (3) --- (4) --- (5) --- (6)
 Money_Word_Problems/267392: I have a total of \$6000 invested in two simple interest accounts. The annual simple interest rate on one account is 9%. The annual simple interest rate on the second account is 6%. How much is invested in each account if both accounts earn the same amount of interest?1 solutions Answer 196253 by drk(1908)   on 2010-02-08 21:37:59 (Show Source): You can put this solution on YOUR website!This is an I = PRT problem. we have the formula I = PRT and another I = PRT. From above, we get I = x(.09)(1) and I = (6000-x)(.06)(1) since interest is equal set them equal to get .09x = 360 - .06x adding .06x we get .15x = 360 dividing, we get x = 2400 at 9% 6000-x = 3600 at 6%.
 Rectangles/267389: find the area of a rectangle that measures 2 2/3 inches by 36 1/2 inches1 solutions Answer 196252 by drk(1908)   on 2010-02-08 21:34:40 (Show Source): You can put this solution on YOUR website!step 1 - turn your numbers into improper fractions to get (8/3) and (73/2) step 2 - area = length x width so we get a = (8/3)*(73/2) = 292/3 = 97 1/3 square inches
 Numbers_Word_Problems/267390: unit digit of a sum 11^11 + 14^14 + 16^16 whats the unit digit of this sum1 solutions Answer 196250 by drk(1908)   on 2010-02-08 21:32:15 (Show Source): You can put this solution on YOUR website!Look for patterns: 11^1 = 11 11^2 = 121 11^3 = 1331 I see the pattern of ending in 1. --- 14^1 = 14 14^2 = 196 14^3 = 2744 when the power is odd it ends in 4, and when it is even it ends in 6. --- 16^1 = 16 16^2 = 256 16^3 = 4096 The units digit is always 8. --- we get 1 + 6 + 6 = 13 The final units digit will be 3.
 Quadratic-relations-and-conic-sections/267384: Find the vertex. Is the vertex a maximum or minimum point? Graph the parabola. a(x) = x^2 -4x +41 solutions Answer 196249 by drk(1908)   on 2010-02-08 21:29:00 (Show Source): You can put this solution on YOUR website!Factoring the original equation, we get (x-2)*(x-2) However, that can be expressed as (x-2)^2 SInce there is no number after the squared binomial, the vertex form of this is y = (x-2)^2 + 0 The vertex is "opposite of the inside number, outside number" so the vertex is (2,0) The vertex shows us a minimum Here is the graph
 test/267380: Given y=x/(x^2+1), use the algebraic tests to determine symmetry with respect to both axes and the origin.1 solutions Answer 196248 by drk(1908)   on 2010-02-08 21:27:06 (Show Source): You can put this solution on YOUR website!To be symmetric to the x axis replace y with -y. we get -y=x/(x^2+1) which is y=-x/(x^2+1) or f(x) - - - > -f(x) therefore, not symmetric to the x axis ----- To be symmetric to the y axis replace x with -x. we get y = -x/(x^2+1) or f(x) - - -> -f(x) therefore, not symmetric to the x axis ----- To be symmetric to the origin replace x with -x AND y with -y. we get -y=-x/(x^2+1) which is y=x/(x^2+1) f(x) - - - -> f(x) Therefore, symmetric to origin. ----- here is the graph.
 Problems-with-consecutive-odd-even-integers/267375: Find two consecutive integers whose product is 6 less than the square of the larger number.1 solutions Answer 196247 by drk(1908)   on 2010-02-08 21:21:29 (Show Source): You can put this solution on YOUR website! step 1 -expand both sides to get step 2 - combine like terms on the right to get step 3 - set = 0 as step 4 - solve for x to get ---- we get x = 5 x + 1 = 6
 logarithm/267340: solve equation for x and round to nearest two decimal places.1 solutions Answer 196246 by drk(1908)   on 2010-02-08 21:18:40 (Show Source): You can put this solution on YOUR website!we start with step 1 - subtraction of logs means divide the terms as step 2 reduce the fraction to get step 3 - rewrite using exponents as step 4 - divide to get
 Quadratic-relations-and-conic-sections/267239: Identify the conic x^2-4y^2-4x-8y-4=0 and find its center and foci1 solutions Answer 196225 by drk(1908)   on 2010-02-08 20:16:51 (Show Source): You can put this solution on YOUR website!This conic is a hyperbola. The adjusted equation after completing the square is or The center is (2, -2) The foci are sqrt(12+3) = sqrt(15) The coordinates of the foci are (2 +- sqrt(15), -2)
 Miscellaneous_Word_Problems/267237: A group of 64 people attend a ball game. There were 3 times as many childre as there were adults in the group. Write a system of equations that you could use to set up this problem where a is the number of adults and c is the number of children in the group. Solve the system of equations for c, the number of children in the group.1 solutions Answer 196179 by drk(1908)   on 2010-02-08 17:19:20 (Show Source): You can put this solution on YOUR website!(i) (ii) by substitution, we get (iii) we get (iv) so
 Pythagorean-theorem/267232: The diagonal of a computer monitor is measured to be 17 inches. If the width of the monitor is 12 inches, find the height of the monitor to the nearest inch. what is the height ? i have to show all work... thanks for helping1 solutions Answer 196178 by drk(1908)   on 2010-02-08 17:12:14 (Show Source): You can put this solution on YOUR website!What we have is Pythagorean theorem or from above, we have squaring 12 and 17 we get subtracting 144 we get by square roots we get this rounds to 12 inches
 Inequalities/267234: how to use formula A=s^2 for square 11 in length/11 in width1 solutions Answer 196177 by drk(1908)   on 2010-02-08 17:08:22 (Show Source): You can put this solution on YOUR website!Area = side x side our side = 11 so we get a = 11 x 11 = 121 square inches
 Polynomials-and-rational-expressions/267203: I am trying to help my child with her homework. So, if you can explain it to me, maybe I can explain it to her.....without GIVING her the answer! Find all of the zeros of the function: I know how to figure out how many positive and negative zeros, but I don't understand how to figure out how many imaginary zeros. Then I don't know how to find all of the zeros.1 solutions Answer 196176 by drk(1908)   on 2010-02-08 17:07:13 (Show Source): You can put this solution on YOUR website! first we use a technique called P-N-I This gives us the positive negative and imaginary zero combinations P . . . N . . . I 3 . . . 1 . . . 0 1 . . . .1 . . . 2 So, I see that we must have 1 negative root somewhere. Next I apply synthetic division to get roots. -1 // 1 . . . . -15 . . . . 70 . . . . -70 . . . . -156 . . . . . . . . . . .-1 . . . . 16 . . . . .-86 . . . . 156 . . . . .1 . . . . .-16 . . . 86 . . . . .-156 . . . .0 and then 6// 1 . . . . -16 . . . . 86 . . . . -156 . . . . . . . . . . 6 . . . . -60 . . . .156 . . . . .1 . . . -10 . . . 26 . . . . .0 So we know that -1 and 6 are roots. Now we can factor x^2 - 10x + 26 using the quadratic as and then which gives us imaginary answers of ----- So, in total we have the following roots: -6, 6, and 5 +-i
 Linear_Equations_And_Systems_Word_Problems/267202: Ina Crespo rowed 7.5 miles down the Habashabee River in 1.5 hrs, but the return trip took her 2.5 hrs. Find the rate Ina rows in still water and the rate of the current1 solutions Answer 196162 by drk(1908)   on 2010-02-08 16:19:18 (Show Source): You can put this solution on YOUR website!This is an RTD problem. Here is a table based on the given information rowing . . . . . . . rate . . . . . . . . . time . . . . . . . . . . distance upriver. . . . . . . .r -c. . . . . . . . . . 2.5. . . . . . . . . . . . 7.5 downriver. . . . . .r + c. . . . . . . . . .1.5 . . . . . . . . . . . 7.5 total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . rate x time = distance. The distance are equal, so the rate x time parts are also equal. We get and we get adding down, we get and then Now,
 Graphs/267197: The top part says - Graph each inequality in a coordinate plane. 5. x < y I have no idea how to solve this as it gives me no numbers. She only have us examples such as 5x-4y>10.1 solutions Answer 196159 by drk(1908)   on 2010-02-08 16:13:31 (Show Source): You can put this solution on YOUR website!Maybe think about this as y > x + 0 now the slope = 1 and the y intercept is 0. put a dot at (0,0) now move 1 unit up and 1 unit to the right and place a second dot. connect the dots with a dashed line. shade up (away) from you. looks like this
 Parallelograms/267199: what is the perimeter of a parallelogram where one side is 12m and the other is 8m? 1 solutions Answer 196158 by drk(1908)   on 2010-02-08 16:10:50 (Show Source): You can put this solution on YOUR website!Perimeter means add all sides. IN our case that would be 12 + 8 + 12 + 8 = 40m
 Equations/267198: how would i find out the answer too the problem 16=4w+2w-21 solutions Answer 196157 by drk(1908)   on 2010-02-08 16:10:03 (Show Source): You can put this solution on YOUR website!here is the original question step 1 - combine like terms on the right to get step 2 - add 2 to get step 3 - divide by 6 to get
 Circles/267155: what is the area of an ellipse with the major axis 20m and the minor axis 10m?1 solutions Answer 196156 by drk(1908)   on 2010-02-08 16:07:18 (Show Source): You can put this solution on YOUR website!The formula for area of ellipse is where a and b are major and minor axis * Note if a = r and b = r as in a circle, then the area would be pir^2 --- 1/2 major = 10 1/2 minor = 5 so, or 56.25*pi meters squared.
 Graphs/267126: Taking an on-line class and cannot find any examples of this in my book and I am at a loss. I can sketch graphs like 3x-2y =6, but I don't know how to solve and sketch greater than, less than, and greater than/less than equal to problems. Thank you. Sketch the graph of 9 + 2y >= 5. (9 + 2 y greather than/equal to 5) 1 solutions Answer 196105 by drk(1908)   on 2010-02-08 12:50:57 (Show Source): You can put this solution on YOUR website!Here are the general steps: (1) solve for y. * remember the negative 1 rule - if you multiply or divide by a negative, you reverse the inequality sign. (2) if you see y > or y >= then shade up or away from you. (3) if you see y < or y <= then shade down or toward you. (4) If you see =, then draw a sold line (5) if you do not see = , then draw a dashed (dotted) line. That should help. ---- Sketch the graph of 9x + 2y >= 5. (9x + 2 y greater than/equal to 5) step 1 - solve for y as y >= (-9/2)x + (5/2) step 2 - slope = (-9/2), y intercept = (5/2). Plot y intercept and then create a second dot with the slope. step 3 - draw solid line because =. step 4 - shade up and away because of >. looks like this
 Matrices-and-determiminant/267123: find the determinant of this matrix [A -2 O] [4 A -4]1 solutions Answer 196102 by drk(1908)   on 2010-02-08 12:43:21 (Show Source): You can put this solution on YOUR website!This is a 2 x 3 matrix. You cannot find determinants of non-square matricies.
 Matrices-and-determiminant/267121: determine whether the given systems are solvable 1. x+2y+3z =1 -x+y =-2 2x-3x+z =0 2. x+2y+3z =-1 4x+5y+6z =0 7x+8y+9z =11 solutions Answer 196100 by drk(1908)   on 2010-02-08 12:42:12 (Show Source): You can put this solution on YOUR website!(1) is solvable (2) not solvable - line 2 and three will cancel each other out
 Miscellaneous_Word_Problems/267120: Bob gave 4/5 of his pencils to Barb, then gave 2/3 of the remaining pencils to Bonnie. Bob ended up with 10 pencils left, how many did he start with?1 solutions Answer 196095 by drk(1908)   on 2010-02-08 12:19:31 (Show Source): You can put this solution on YOUR website!bob gave (4/5) P bob left (1/5) p --- bob gave (2/3)(1/5)p bob left (1/3)(1/5)p = 10 --- (1/3)(1/5)p = 10 becomes (1/15)p = 10 multiply by 15 to get p = 150 ---
 Pythagorean-theorem/267117: The shortest side of a triangle is one half the length of the middle side, plus 2 cm. The longest side of the triangle is one and one-half times the length of the middle side, less 2 cm. The perimeter of the triangle is 60 cm. How long are each of the sides?1 solutions Answer 196094 by drk(1908)   on 2010-02-08 12:16:55 (Show Source): You can put this solution on YOUR website!S = (1/2)m + 2 m = m L = (3/2)m - 2 P = 60 ---- P = short + middle + long 60 = (1/2)m + 2 + m +(3/2)m - 2 combine like terms to get 60 = 3m divide to get m = 20 s = 12 L = 28