-20(x+3)(x+2)=0

Solution for -20(x+3)(x+2)=0 equation:

-20(x+3)(x+2)=0

We multiply parentheses ..

-20(+x^2+2x+3x+6)=0

We multiply parentheses

-20x^2-40x-60x-120=0

We add all the numbers together, and all the variables

-20x^2-100x-120=0

a = -20; b = -100; c = -120;
Δ = b2-4ac
Δ = -1002-4·(-20)·(-120)
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{-(-100)-20}{2*-20}=\frac{80}{-40}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-100)+20}{2*-20}=\frac{120}{-40}
=-3
$