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

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

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