D=0.0052s^2+0.13s

Solution for D=0.0052s^2+0.13s equation:

=0.0052D^2+0.13D

We move all terms to the left:

-(0.0052D^2+0.13D)=0

We get rid of parentheses

-0.0052D^2-0.13D=0

a = -0.0052; b = -0.13; c = 0;
Δ = b2-4ac
Δ = -0.132-4·(-0.0052)·0
Δ = 0.0169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.13)-\sqrt{0.0169}}{2*-0.0052}=\frac{0.13-\sqrt{0.0169}}{-0.0104}
$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.13)+\sqrt{0.0169}}{2*-0.0052}=\frac{0.13+\sqrt{0.0169}}{-0.0104}
$