(3y+-5)(-4y+-7)=0

Solution for (3y+-5)(-4y+-7)=0 equation:

(3y+-5)(-4y+-7)=0

We add all the numbers together, and all the variables

(3y-5)(-4y-7)=0

We multiply parentheses ..

(-12y^2-21y+20y+35)=0

We get rid of parentheses

-12y^2-21y+20y+35=0

We add all the numbers together, and all the variables

-12y^2-1y+35=0

a = -12; b = -1; c = +35;
Δ = b2-4ac
Δ = -12-4·(-12)·35
Δ = 1681
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1681}=41$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-41}{2*-12}=\frac{-40}{-24}
=1+2/3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+41}{2*-12}=\frac{42}{-24}
=-1+3/4
$