-16x^2+256=0

Solution for -16x^2+256=0 equation:

-16x^2+256=0

a = -16; b = 0; c = +256;
Δ = b2-4ac
Δ = 02-4·(-16)·256
Δ = 16384
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16384}=128$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-128}{2*-16}=\frac{-128}{-32}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+128}{2*-16}=\frac{128}{-32}
=-4
$