v^2+8v-80=0

Solution for v^2+8v-80=0 equation:

v^2+8v-80=0

a = 1; b = 8; c = -80;
Δ = b2-4ac
Δ = 82-4·1·(-80)
Δ = 384
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{384}=\sqrt{64*6}=\sqrt{64}*\sqrt{6}=8\sqrt{6}$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-8\sqrt{6}}{2*1}=\frac{-8-8\sqrt{6}}{2}
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+8\sqrt{6}}{2*1}=\frac{-8+8\sqrt{6}}{2}
$