X^2+20x-360=0

Solution for X^2+20x-360=0 equation:

X^2+20X-360=0

a = 1; b = 20; c = -360;
Δ = b2-4ac
Δ = 202-4·1·(-360)
Δ = 1840
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1840}=\sqrt{16*115}=\sqrt{16}*\sqrt{115}=4\sqrt{115}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-4\sqrt{115}}{2*1}=\frac{-20-4\sqrt{115}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+4\sqrt{115}}{2*1}=\frac{-20+4\sqrt{115}}{2}
$