0=-q^2-60q+4000

Solution for 0=-q^2-60q+4000 equation:

0=-q^2-60q+4000

We move all terms to the left:

0-(-q^2-60q+4000)=0

We add all the numbers together, and all the variables

-(-q^2-60q+4000)=0

We get rid of parentheses

q^2+60q-4000=0

a = 1; b = 60; c = -4000;
Δ = b2-4ac
Δ = 602-4·1·(-4000)
Δ = 19600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{19600}=140$
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-140}{2*1}=\frac{-200}{2}
=-100
$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+140}{2*1}=\frac{80}{2}
=40
$