x2-12x=64

Solution for x2-12x=64 equation:

x2-12x=64

We move all terms to the left:

x2-12x-(64)=0

We add all the numbers together, and all the variables

x^2-12x-64=0

a = 1; b = -12; c = -64;
Δ = b2-4ac
Δ = -122-4·1·(-64)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-20}{2*1}=\frac{-8}{2}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+20}{2*1}=\frac{32}{2}
=16
$