(3x+3)(12x-6)=0

Solution for (3x+3)(12x-6)=0 equation:

(3x+3)(12x-6)=0

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

36x^2+18x-18=0

a = 36; b = 18; c = -18;
Δ = b2-4ac
Δ = 182-4·36·(-18)
Δ = 2916
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2916}=54$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-54}{2*36}=\frac{-72}{72}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+54}{2*36}=\frac{36}{72}
=1/2
$