5y(y-1)+4(1-y)=0

Solution for 5y(y-1)+4(1-y)=0 equation:

5y(y-1)+4(1-y)=0

We add all the numbers together, and all the variables

5y(y-1)+4(-1y+1)=0

We multiply parentheses

5y^2-5y-4y+4=0

We add all the numbers together, and all the variables

5y^2-9y+4=0

a = 5; b = -9; c = +4;
Δ = b2-4ac
Δ = -92-4·5·4
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-1}{2*5}=\frac{8}{10}
=4/5
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+1}{2*5}=\frac{10}{10}
=1
$