x^2+20x-171=0

Solution for x^2+20x-171=0 equation:

x^2+20x-171=0

a = 1; b = 20; c = -171;
Δ = b2-4ac
Δ = 202-4·1·(-171)
Δ = 1084
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:

$\sqrt{\Delta}=\sqrt{1084}=\sqrt{4*271}=\sqrt{4}*\sqrt{271}=2\sqrt{271}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-2\sqrt{271}}{2*1}=\frac{-20-2\sqrt{271}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+2\sqrt{271}}{2*1}=\frac{-20+2\sqrt{271}}{2}
$