0=-2.5x^2+200x

Solution for 0=-2.5x^2+200x equation:

0=-2.5x^2+200x

We move all terms to the left:

0-(-2.5x^2+200x)=0

We add all the numbers together, and all the variables

-(-2.5x^2+200x)=0

We get rid of parentheses

2.5x^2-200x=0

a = 2.5; b = -200; c = 0;
Δ = b2-4ac
Δ = -2002-4·2.5·0
Δ = 40000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{40000}=200$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-200)-200}{2*2.5}=\frac{0}{5}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-200)+200}{2*2.5}=\frac{400}{5}
=80
$