-4x^2-64x-220=0

Solution for -4x^2-64x-220=0 equation:

-4x^2-64x-220=0

a = -4; b = -64; c = -220;
Δ = b2-4ac
Δ = -642-4·(-4)·(-220)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-24}{2*-4}=\frac{40}{-8}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+24}{2*-4}=\frac{88}{-8}
=-11
$