-7y-4=4y(8-6)-64

Solution for -7y-4=4y(8-6)-64 equation:

-7y-4=4y(8-6)-64

We move all terms to the left:

-7y-4-(4y(8-6)-64)=0

We add all the numbers together, and all the variables

-7y-(4y2-64)-4=0

We get rid of parentheses

-7y-4y2+64-4=0

We add all the numbers together, and all the variables

-4y^2-7y+60=0

a = -4; b = -7; c = +60;
Δ = b2-4ac
Δ = -72-4·(-4)·60
Δ = 1009
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{1009}}{2*-4}=\frac{7-\sqrt{1009}}{-8}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{1009}}{2*-4}=\frac{7+\sqrt{1009}}{-8}
$