-0.006d^2+0.6d=-3

Solution for -0.006d^2+0.6d=-3 equation:

-0.006d^2+0.6d=-3

We move all terms to the left:

-0.006d^2+0.6d-(-3)=0

We add all the numbers together, and all the variables

-0.006d^2+0.6d+3=0

a = -0.006; b = 0.6; c = +3;
Δ = b2-4ac
Δ = 0.62-4·(-0.006)·3
Δ = 0.432
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{-(0.6)-\sqrt{0.432}}{2*-0.006}=\frac{-0.6-\sqrt{0.432}}{-0.012}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.6)+\sqrt{0.432}}{2*-0.006}=\frac{-0.6+\sqrt{0.432}}{-0.012}
$