-9x^2=-64

Solution for -9x^2=-64 equation:

-9x^2=-64

We move all terms to the left:

-9x^2-(-64)=0

We add all the numbers together, and all the variables

-9x^2+64=0

a = -9; b = 0; c = +64;
Δ = b2-4ac
Δ = 02-4·(-9)·64
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-48}{2*-9}=\frac{-48}{-18}
=2+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+48}{2*-9}=\frac{48}{-18}
=-2+2/3
$