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

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

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

We multiply parentheses ..

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

We multiply parentheses

8x^2-16x+32x-64=0

We add all the numbers together, and all the variables

8x^2+16x-64=0

a = 8; b = 16; c = -64;
Δ = b2-4ac
Δ = 162-4·8·(-64)
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-48}{2*8}=\frac{-64}{16}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+48}{2*8}=\frac{32}{16}
=2
$