(x+2)(2x-12)=0

Solution for (x+2)(2x-12)=0 equation:

(x+2)(2x-12)=0

We multiply parentheses ..

(+2x^2-12x+4x-24)=0

We get rid of parentheses

2x^2-12x+4x-24=0

We add all the numbers together, and all the variables

2x^2-8x-24=0

a = 2; b = -8; c = -24;
Δ = b2-4ac
Δ = -82-4·2·(-24)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-16}{2*2}=\frac{-8}{4}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+16}{2*2}=\frac{24}{4}
=6
$