91,7=44,175*x-2,85*x^2

Solution for 91,7=44,175*x-2,85*x^2 equation:

91.7=44.175x-2.85x^2

We move all terms to the left:

91.7-(44.175x-2.85x^2)=0

We get rid of parentheses

2.85x^2-44.175x+91.7=0

a = 2.85; b = -44.175; c = +91.7;
Δ = b2-4ac
Δ = -44.1752-4·2.85·91.7
Δ = 906.050625
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{-(-44.175)-\sqrt{906.050625}}{2*2.85}=\frac{44.175-\sqrt{906.050625}}{5.7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-44.175)+\sqrt{906.050625}}{2*2.85}=\frac{44.175+\sqrt{906.050625}}{5.7}
$