18q-0.4q^2=200

Solution for 18q-0.4q^2=200 equation:

18q-0.4q^2=200

We move all terms to the left:

18q-0.4q^2-(200)=0

a = -0.4; b = 18; c = -200;
Δ = b2-4ac
Δ = 182-4·(-0.4)·(-200)
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-2}{2*-0.4}=\frac{-20}{-0.8}
=+25
$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+2}{2*-0.4}=\frac{-16}{-0.8}
=+20
$