(2x-6)(9x+9)=0

Solution for (2x-6)(9x+9)=0 equation:

(2x-6)(9x+9)=0

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

18x^2-36x-54=0

a = 18; b = -36; c = -54;
Δ = b2-4ac
Δ = -362-4·18·(-54)
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*18}=\frac{-36}{36}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+72}{2*18}=\frac{108}{36}
=3
$