x(680-4x)=0

Solution for x(680-4x)=0 equation:

x(680-4x)=0

We add all the numbers together, and all the variables

x(-4x+680)=0

We multiply parentheses

-4x^2+680x=0

a = -4; b = 680; c = 0;
Δ = b2-4ac
Δ = 6802-4·(-4)·0
Δ = 462400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{462400}=680$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(680)-680}{2*-4}=\frac{-1360}{-8}
=+170
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(680)+680}{2*-4}=\frac{0}{-8}
=0
$