8x(-2x-8)=4

Solution for 8x(-2x-8)=4 equation:

8x(-2x-8)=4

We move all terms to the left:

8x(-2x-8)-(4)=0

We multiply parentheses

-16x^2-64x-4=0

a = -16; b = -64; c = -4;
Δ = b2-4ac
Δ = -642-4·(-16)·(-4)
Δ = 3840
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:

$\sqrt{\Delta}=\sqrt{3840}=\sqrt{256*15}=\sqrt{256}*\sqrt{15}=16\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-16\sqrt{15}}{2*-16}=\frac{64-16\sqrt{15}}{-32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+16\sqrt{15}}{2*-16}=\frac{64+16\sqrt{15}}{-32}
$