(7y-5)(8y-1)=0

Solution for (7y-5)(8y-1)=0 equation:

(7y-5)(8y-1)=0

We multiply parentheses ..

(+56y^2-7y-40y+5)=0

We get rid of parentheses

56y^2-7y-40y+5=0

We add all the numbers together, and all the variables

56y^2-47y+5=0

a = 56; b = -47; c = +5;
Δ = b2-4ac
Δ = -472-4·56·5
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-47)-33}{2*56}=\frac{14}{112}
=1/8
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-47)+33}{2*56}=\frac{80}{112}
=5/7
$