-4v^2-24v+64=0

Solution for -4v^2-24v+64=0 equation:

-4v^2-24v+64=0

a = -4; b = -24; c = +64;
Δ = b2-4ac
Δ = -242-4·(-4)·64
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-24)-40}{2*-4}=\frac{-16}{-8}
=+2
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-24)+40}{2*-4}=\frac{64}{-8}
=-8
$