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

Solution for (2x-4)(8x+4)=0 equation:

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

We multiply parentheses ..

(+16x^2+8x-32x-16)=0

We get rid of parentheses

16x^2+8x-32x-16=0

We add all the numbers together, and all the variables

16x^2-24x-16=0

a = 16; b = -24; c = -16;
Δ = b2-4ac
Δ = -242-4·16·(-16)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-24)-40}{2*16}=\frac{-16}{32}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-24)+40}{2*16}=\frac{64}{32}
=2
$