(3x-6)(9x+6)=0

Solution for (3x-6)(9x+6)=0 equation:

(3x-6)(9x+6)=0

We multiply parentheses ..

(+27x^2+18x-54x-36)=0

We get rid of parentheses

27x^2+18x-54x-36=0

We add all the numbers together, and all the variables

27x^2-36x-36=0

a = 27; b = -36; c = -36;
Δ = b2-4ac
Δ = -362-4·27·(-36)
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-72}{2*27}=\frac{-36}{54}
=-2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+72}{2*27}=\frac{108}{54}
=2
$