(2-y)(5y-9)=0

Solution for (2-y)(5y-9)=0 equation:

(2-y)(5y-9)=0

We add all the numbers together, and all the variables

(-1y+2)(5y-9)=0

We multiply parentheses ..

(-5y^2+9y+10y-18)=0

We get rid of parentheses

-5y^2+9y+10y-18=0

We add all the numbers together, and all the variables

-5y^2+19y-18=0

a = -5; b = 19; c = -18;
Δ = b2-4ac
Δ = 192-4·(-5)·(-18)
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{-(19)-1}{2*-5}=\frac{-20}{-10}
=+2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+1}{2*-5}=\frac{-18}{-10}
=1+4/5
$