SOLUTION: I apologize for having to ask two questions but they are the only two that I'm totally stumped on. I appreciate your help very, very much!! This also is a quadratic function.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I apologize for having to ask two questions but they are the only two that I'm totally stumped on. I appreciate your help very, very much!! This also is a quadratic function.       Log On


   

Question 168650This question is from textbook Intermediate Algebra
: I apologize for having to ask two questions but they are the only two that I'm totally stumped on. I appreciate your help very, very much!! This also is a quadratic function.

"Solve each equation for the indicated variable"
10p%5E2c%5E2+%2B+7pcr+=+12r%5E2 Solve for r This question is from textbook Intermediate Algebra

Found 2 solutions by Alan3354, stanbon:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
10p%5E2c%5E2+%2B+7pcr+=+12r%5E2 Solve for r
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12r%5E2+-+%287pc%29r+-+10p%5E2c%5E2+=+0
Factor it
(4r - 5pc)*(3r + 2pc) = 0
r = 5pc/4
r = -2pc/3



Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
10p^2c^2 + 7pcr = 12r^2
12r^2 - 7pcr - 10p^2c^2 = 0
Use the quadratic formula:
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r = [7pc +- sqrt(49p^2c^2 - 4*12*-10p^2c^2)]/24
r = [7pc +- sqrt(529p^2c^2)]/24
r = [7pc +- 23pc]/24
r = [30pc]/24 or r = [-16pc]/24
r = [15/12]pc or [-2/3]pc
===============================
Cheers,
Stan H.