(X-8)(x-12)=0

Solution for (X-8)(x-12)=0 equation:

(X-8)(X-12)=0

We multiply parentheses ..

(+X^2-12X-8X+96)=0

We get rid of parentheses

X^2-12X-8X+96=0

We add all the numbers together, and all the variables

X^2-20X+96=0

a = 1; b = -20; c = +96;
Δ = b2-4ac
Δ = -202-4·1·96
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-4}{2*1}=\frac{16}{2}
=8
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+4}{2*1}=\frac{24}{2}
=12
$