6=-0.01x^2+1.18x

Solution for 6=-0.01x^2+1.18x equation:

6=-0.01x^2+1.18x

We move all terms to the left:

6-(-0.01x^2+1.18x)=0

We get rid of parentheses

0.01x^2-1.18x+6=0

a = 0.01; b = -1.18; c = +6;
Δ = b2-4ac
Δ = -1.182-4·0.01·6
Δ = 1.1524
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{-(-1.18)-\sqrt{1.1524}}{2*0.01}=\frac{1.18-\sqrt{1.1524}}{0.02}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.18)+\sqrt{1.1524}}{2*0.01}=\frac{1.18+\sqrt{1.1524}}{0.02}
$