-36x^2=-81

Solution for -36x^2=-81 equation:

-36x^2=-81

We move all terms to the left:

-36x^2-(-81)=0

We add all the numbers together, and all the variables

-36x^2+81=0

a = -36; b = 0; c = +81;
Δ = b2-4ac
Δ = 02-4·(-36)·81
Δ = 11664
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{11664}=108$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-108}{2*-36}=\frac{-108}{-72}
=1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+108}{2*-36}=\frac{108}{-72}
=-1+1/2
$