8=0.01x^2+0.05x

Solution for 8=0.01x^2+0.05x equation:

8=0.01x^2+0.05x

We move all terms to the left:

8-(0.01x^2+0.05x)=0

We get rid of parentheses

-0.01x^2-0.05x+8=0

a = -0.01; b = -0.05; c = +8;
Δ = b2-4ac
Δ = -0.052-4·(-0.01)·8
Δ = 0.3225
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{-(-0.05)-\sqrt{0.3225}}{2*-0.01}=\frac{0.05-\sqrt{0.3225}}{-0.02}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.05)+\sqrt{0.3225}}{2*-0.01}=\frac{0.05+\sqrt{0.3225}}{-0.02}
$