y(2y-1.8)=0

Solution for y(2y-1.8)=0 equation:

y(2y-1.8)=0

We multiply parentheses

2y^2-1.8y=0

a = 2; b = -1.8; c = 0;
Δ = b2-4ac
Δ = -1.82-4·2·0
Δ = 3.24
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{-(-1.8)-\sqrt{3.24}}{2*2}=\frac{1.8-\sqrt{3.24}}{4}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.8)+\sqrt{3.24}}{2*2}=\frac{1.8+\sqrt{3.24}}{4}
$