I'm getting different answer from answer key.
Solving $(2y-4)(2y+1) = (2y-2)^2$
FOIL left side $4y^2+2y-8y-4 = (2y-2)^2$
Right side $4y^2+2y-8y-4 = 4y^2+4 $
Subtract $4y^2$ from both sides
$2y-8y-4 = 4 $
Combine $y$
$6y-4 = 4$
add 4 to both sides
$6y = 8$
But the answer key has $y=4$