(8x-8)(9x+9)=0

Solution for (8x-8)(9x+9)=0 equation:

(8x-8)(9x+9)=0

We multiply parentheses ..

(+72x^2+72x-72x-72)=0

We get rid of parentheses

72x^2+72x-72x-72=0

We add all the numbers together, and all the variables

72x^2-72=0

a = 72; b = 0; c = -72;
Δ = b2-4ac
Δ = 02-4·72·(-72)
Δ = 20736
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{20736}=144$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-144}{2*72}=\frac{-144}{144}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+144}{2*72}=\frac{144}{144}
=1
$