900=0.6q^2-30q+1,000

Solution for 900=0.6q^2-30q+1,000 equation:

900=0.6q^2-30q+1.000

We move all terms to the left:

900-(0.6q^2-30q+1.000)=0

We get rid of parentheses

-0.6q^2+30q-1.000+900=0

We add all the numbers together, and all the variables

-0.6q^2+30q+899=0

a = -0.6; b = 30; c = +899;
Δ = b2-4ac
Δ = 302-4·(-0.6)·899
Δ = 3057.6
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-\sqrt{3057.6}}{2*-0.6}=\frac{-30-\sqrt{3057.6}}{-1.2}
$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+\sqrt{3057.6}}{2*-0.6}=\frac{-30+\sqrt{3057.6}}{-1.2}
$