# Math Help - Solve for x

1. ## Solve for x

x/6 = 6/x-8
I know the answer is x = 4 + 2 times the square root of 13, but I don't know how to attain it.

2. Originally Posted by Chuck
x/6 = 6/x-8
I know the answer is x = 4 + 2 times the square root of 13, but I don't know how to attain it.
$\frac{x}{6} = \frac{6}{x-8}$

$\frac{x(x-8)}{6} = 6$

$x(x-8) = 36$

$x^2- 8x - 36 = 0$

$x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}$, where $a = 1, b = -8, c = -36$.

3. Thank you. I didn't know that formula, but I do now.