4x(90-x)-8x=0

Solution for 4x(90-x)-8x=0 equation:

4x(90-x)-8x=0

We add all the numbers together, and all the variables

4x(-1x+90)-8x=0

We add all the numbers together, and all the variables

-8x+4x(-1x+90)=0

We multiply parentheses

-4x^2-8x+360x=0

We add all the numbers together, and all the variables

-4x^2+352x=0

a = -4; b = 352; c = 0;
Δ = b2-4ac
Δ = 3522-4·(-4)·0
Δ = 123904
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{123904}=352$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(352)-352}{2*-4}=\frac{-704}{-8}
=+88
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(352)+352}{2*-4}=\frac{0}{-8}
=0
$