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

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

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

We multiply parentheses ..

(+81x^2+18x+18x+4)-9=0

We get rid of parentheses

81x^2+18x+18x+4-9=0

We add all the numbers together, and all the variables

81x^2+36x-5=0

a = 81; b = 36; c = -5;
Δ = b2-4ac
Δ = 362-4·81·(-5)
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{-(36)-54}{2*81}=\frac{-90}{162}
=-5/9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(36)+54}{2*81}=\frac{18}{162}
=1/9
$