(x)=-0.2x^2+860x-240000

Solution for (x)=-0.2x^2+860x-240000 equation:

(x)=-0.2x^2+860x-240000

We move all terms to the left:

(x)-(-0.2x^2+860x-240000)=0

We get rid of parentheses

0.2x^2-860x+x+240000=0

We add all the numbers together, and all the variables

0.2x^2-859x+240000=0

a = 0.2; b = -859; c = +240000;
Δ = b2-4ac
Δ = -8592-4·0.2·240000
Δ = 545881
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-859)-\sqrt{545881}}{2*0.2}=\frac{859-\sqrt{545881}}{0.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-859)+\sqrt{545881}}{2*0.2}=\frac{859+\sqrt{545881}}{0.4}
$