Question 39890
First we isolate the radical and then square both sides...so from
sqrt(2y+7) + 4 = y
sqrt(2y+7) = y - 4
2y + 7 = (y - 4)^2
2y + 7 = y^2 - 8y + 16 now collect like terms and solve
y^2 - 10y + 9 = 0
(y-9)(y-1) = 0
y = 9 or y = 1
Yo have to check these, however, and only y = 9 checks out. y = 1 doesn't check.  Thus,
y = 9