(3-y)(5y-8)=0

Solution for (3-y)(5y-8)=0 equation:

(3-y)(5y-8)=0

We add all the numbers together, and all the variables

(-1y+3)(5y-8)=0

We multiply parentheses ..

(-5y^2+8y+15y-24)=0

We get rid of parentheses

-5y^2+8y+15y-24=0

We add all the numbers together, and all the variables

-5y^2+23y-24=0

a = -5; b = 23; c = -24;
Δ = b2-4ac
Δ = 232-4·(-5)·(-24)
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(23)-7}{2*-5}=\frac{-30}{-10}
=+3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(23)+7}{2*-5}=\frac{-16}{-10}
=1+3/5
$