(3x-6)(x+6)=0

Solution for (3x-6)(x+6)=0 equation:

(3x-6)(x+6)=0

We multiply parentheses ..

(+3x^2+18x-6x-36)=0

We get rid of parentheses

3x^2+18x-6x-36=0

We add all the numbers together, and all the variables

3x^2+12x-36=0

a = 3; b = 12; c = -36;
Δ = b2-4ac
Δ = 122-4·3·(-36)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-24}{2*3}=\frac{-36}{6}
=-6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+24}{2*3}=\frac{12}{6}
=2
$