x^2+100x-120=0

Solution for x^2+100x-120=0 equation:

x^2+100x-120=0

a = 1; b = 100; c = -120;
Δ = b2-4ac
Δ = 1002-4·1·(-120)
Δ = 10480
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:

$\sqrt{\Delta}=\sqrt{10480}=\sqrt{16*655}=\sqrt{16}*\sqrt{655}=4\sqrt{655}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-4\sqrt{655}}{2*1}=\frac{-100-4\sqrt{655}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+4\sqrt{655}}{2*1}=\frac{-100+4\sqrt{655}}{2}
$