0=20x^2+80x

Solution for 0=20x^2+80x equation:

0=20x^2+80x

We move all terms to the left:

0-(20x^2+80x)=0

We add all the numbers together, and all the variables

-(20x^2+80x)=0

We get rid of parentheses

-20x^2-80x=0

a = -20; b = -80; c = 0;
Δ = b2-4ac
Δ = -802-4·(-20)·0
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-80)-80}{2*-20}=\frac{0}{-40}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-80)+80}{2*-20}=\frac{160}{-40}
=-4
$