11x(x-11)-1980=0

Solution for 11x(x-11)-1980=0 equation:

11x(x-11)-1980=0

We multiply parentheses

11x^2-121x-1980=0

a = 11; b = -121; c = -1980;
Δ = b2-4ac
Δ = -1212-4·11·(-1980)
Δ = 101761
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{101761}=319$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-121)-319}{2*11}=\frac{-198}{22}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-121)+319}{2*11}=\frac{440}{22}
=20
$