S=-25m^2+125m

Solution for S=-25m^2+125m equation:

=-25S^2+125S

We move all terms to the left:

-(-25S^2+125S)=0

We get rid of parentheses

25S^2-125S=0

a = 25; b = -125; c = 0;
Δ = b2-4ac
Δ = -1252-4·25·0
Δ = 15625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$S_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$S_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{15625}=125$
$S_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-125)-125}{2*25}=\frac{0}{50}
=0
$
$S_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-125)+125}{2*25}=\frac{250}{50}
=5
$