Answer:
y = -2 +sqrt(7)
y = -2 - sqrt(7)
Explanation:
y^2 +4y +4 = 7
Factor, recognizing that this is the sum of squares
a^2 +2ab+b^2 = (a+b)^2
(y+2) ^2 = 7
Take the square root of each side
sqrt((y+2) ^2) =± sqrt(7)
y+2 = ± sqrt(7)
Subtract 2 from each side
y+2-2 = -2 ± sqrt(7)
y = -2 ± sqrt(7)