x^2+20*x-8000=0

Solution for x^2+20*x-8000=0 equation:

x^2+20x-8000=0

a = 1; b = 20; c = -8000;
Δ = b2-4ac
Δ = 202-4·1·(-8000)
Δ = 32400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{32400}=180$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-180}{2*1}=\frac{-200}{2}
=-100
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+180}{2*1}=\frac{160}{2}
=80
$