-4x(2x-20)=-16

Solution for -4x(2x-20)=-16 equation:

-4x(2x-20)=-16

We move all terms to the left:

-4x(2x-20)-(-16)=0

We add all the numbers together, and all the variables

-4x(2x-20)+16=0

We multiply parentheses

-8x^2+80x+16=0

a = -8; b = 80; c = +16;
Δ = b2-4ac
Δ = 802-4·(-8)·16
Δ = 6912
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{6912}=\sqrt{2304*3}=\sqrt{2304}*\sqrt{3}=48\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-48\sqrt{3}}{2*-8}=\frac{-80-48\sqrt{3}}{-16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+48\sqrt{3}}{2*-8}=\frac{-80+48\sqrt{3}}{-16}
$