x(x-1)=120

Solution for x(x-1)=120 equation:

x(x-1)=120

We move all terms to the left:

x(x-1)-(120)=0

We multiply parentheses

x^2-1x-120=0

a = 1; b = -1; c = -120;
Δ = b2-4ac
Δ = -12-4·1·(-120)
Δ = 481
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-\sqrt{481}}{2*1}=\frac{1-\sqrt{481}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{481}}{2*1}=\frac{1+\sqrt{481}}{2}
$