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

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

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

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

18x^2-18=0

a = 18; b = 0; c = -18;
Δ = b2-4ac
Δ = 02-4·18·(-18)
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-36}{2*18}=\frac{-36}{36}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+36}{2*18}=\frac{36}{36}
=1
$