$\displaystyle 751 =\pi \* 75^2 [-1/(x+30) + 1/x]$
Find the value of x.
I already tried expanding, but it just makes things worse.
According to my calculator, x should be about 15.5, but I got no way to prove it!
$\displaystyle 751 = 75^{2}\pi \left(\frac{1}{x} - \frac{1}{x+30}\right)$
Is this your equation?
$\displaystyle \frac{751}{75^{2}\pi} = \frac{1}{x} - \frac{1}{x+30}$
$\displaystyle \frac{751}{5625\pi} = \frac{x+30 - x}{x(x+30)}$
$\displaystyle \frac{751}{5625\pi} = \frac{30}{x^{2} + 30x}$
Cross multiply and keep going