0=-0.2x^2+85x-2000

Solution for 0=-0.2x^2+85x-2000 equation:

0=-0.2x^2+85x-2000

We move all terms to the left:

0-(-0.2x^2+85x-2000)=0

We add all the numbers together, and all the variables

-(-0.2x^2+85x-2000)=0

We get rid of parentheses

0.2x^2-85x+2000=0

a = 0.2; b = -85; c = +2000;
Δ = b2-4ac
Δ = -852-4·0.2·2000
Δ = 5625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5625}=75$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-85)-75}{2*0.2}=\frac{10}{0.4}
=25
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-85)+75}{2*0.2}=\frac{160}{0.4}
=400
$