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

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

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

We multiply parentheses ..

(+40y^2-15y+24y-9)=0

We get rid of parentheses

40y^2-15y+24y-9=0

We add all the numbers together, and all the variables

40y^2+9y-9=0

a = 40; b = 9; c = -9;
Δ = b2-4ac
Δ = 92-4·40·(-9)
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-39}{2*40}=\frac{-48}{80}
=-3/5
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+39}{2*40}=\frac{30}{80}
=3/8
$