0.02(a^2)+18.9a-10.68=0

Solution for 0.02(a^2)+18.9a-10.68=0 equation:

0.02(a^2)+18.9a-10.68=0

a = 0.02; b = 18.9; c = -10.68;
Δ = b2-4ac
Δ = 18.92-4·0.02·(-10.68)
Δ = 358.0644
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18.9)-\sqrt{358.0644}}{2*0.02}=\frac{-18.9-\sqrt{358.0644}}{0.04}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18.9)+\sqrt{358.0644}}{2*0.02}=\frac{-18.9+\sqrt{358.0644}}{0.04}
$