P=4x^2-64

Solution for P=4x^2-64 equation:

=4P^2-64

We move all terms to the left:

-(4P^2-64)=0

We get rid of parentheses

-4P^2+64=0

a = -4; b = 0; c = +64;
Δ = b2-4ac
Δ = 02-4·(-4)·64
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-32}{2*-4}=\frac{-32}{-8}
=+4
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+32}{2*-4}=\frac{32}{-8}
=-4
$