X(x+20)=0

Solution for X(x+20)=0 equation:

X(X+20)=0

We multiply parentheses

X^2+20X=0

a = 1; b = 20; c = 0;
Δ = b2-4ac
Δ = 202-4·1·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-20}{2*1}=\frac{-40}{2}
=-20
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+20}{2*1}=\frac{0}{2}
=0
$