y(y-13.2)=0

Solution for y(y-13.2)=0 equation:

y(y-13.2)=0

We multiply parentheses

y^2-13.2y=0

a = 1; b = -13.2; c = 0;
Δ = b2-4ac
Δ = -13.22-4·1·0
Δ = 174.24
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13.2)-\sqrt{174.24}}{2*1}=\frac{13.2-\sqrt{174.24}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13.2)+\sqrt{174.24}}{2*1}=\frac{13.2+\sqrt{174.24}}{2}
$