0=4x2-48x-256

Solution for 0=4x2-48x-256 equation:

0=4x^2-48x-256

We move all terms to the left:

0-(4x^2-48x-256)=0

We add all the numbers together, and all the variables

-(4x^2-48x-256)=0

We get rid of parentheses

-4x^2+48x+256=0

a = -4; b = 48; c = +256;
Δ = b2-4ac
Δ = 482-4·(-4)·256
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(48)-80}{2*-4}=\frac{-128}{-8}
=+16
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(48)+80}{2*-4}=\frac{32}{-8}
=-4
$