y=7y(2)-4

Solution for y=7y(2)-4 equation:

y=7y(2)-4

We move all terms to the left:

y-(7y(2)-4)=0

We add all the numbers together, and all the variables

-(+7y^2-4)+y=0

We get rid of parentheses

-7y^2+y+4=0

a = -7; b = 1; c = +4;
Δ = b2-4ac
Δ = 12-4·(-7)·4
Δ = 113
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{-(1)-\sqrt{113}}{2*-7}=\frac{-1-\sqrt{113}}{-14}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{113}}{2*-7}=\frac{-1+\sqrt{113}}{-14}
$