(x*2-x-2)(9x+36)=0

Solution for (x*2-x-2)(9x+36)=0 equation:

(x*2-x-2)(9x+36)=0

We add all the numbers together, and all the variables

(-1x+x*2-2)(9x+36)=0

We multiply parentheses ..

(-9x^2-36x+18x^2+72x-18x-72)=0

We get rid of parentheses

-9x^2+18x^2-36x+72x-18x-72=0

We add all the numbers together, and all the variables

9x^2+18x-72=0

a = 9; b = 18; c = -72;
Δ = b2-4ac
Δ = 182-4·9·(-72)
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*9}=\frac{-72}{18}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+54}{2*9}=\frac{36}{18}
=2
$