0=20x^2+400x

Solution for 0=20x^2+400x equation:

0=20x^2+400x

We move all terms to the left:

0-(20x^2+400x)=0

We add all the numbers together, and all the variables

-(20x^2+400x)=0

We get rid of parentheses

-20x^2-400x=0

a = -20; b = -400; c = 0;
Δ = b2-4ac
Δ = -4002-4·(-20)·0
Δ = 160000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{160000}=400$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-400)-400}{2*-20}=\frac{0}{-40}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-400)+400}{2*-20}=\frac{800}{-40}
=-20
$