Algebra problem?

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What is the answer of -5 - x over 4x+1 = 10x+15 over 3x? I'm kinda lost...

2007-11-04 08:53:02 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

Cross multiply, getting:
(-5-x)(3x) = (4x+1)(10x+15)
-15x - 3x^2 = 40x^2 +70x +15
43x^2 +85x +15 = 0
x = [-85 +/- 68.15]/86

2007-11-04 09:05:10 · answer #1 · answered by ironduke8159 7 · 0⤊ 0⤋

-( 5 + x)/(4x + 1) = (10x + 15)/3x
-3x(5 + x) = (10x + 15)(4x + 1)
-15x -3x^2 = 40x^2 + 10x + 60x + 15
0 = 43x^2 + 85x + 15

Plug the coefficients into the binomial theorem.
the two solutions are:

x = (-85 +/- sqrt(85^2 - 4*43*15))/2*43
= 99.82 +/- .792

2007-11-04 17:08:35 · answer #2 · answered by dooner75 3 · 0⤊ 0⤋

for future reference see http://en.wikipedia.org/wiki/Quadratic_equation

2007-11-04 17:20:00 · answer #3 · answered by Anonymous · 0⤊ 0⤋