Answer:
y = 4
Explanation:
y - 1 = √y + 5
(y - 1)² = y + 5 (Square both sides)
y² - 2y + 1 = y + 5 (Expand left side)
y² - 3y - 4 = 0 (Subtract y and 5 from both sides)
(y + 1) (y - 4) = 0 (Factor)
y = -1, 4 (Use ZPP)
When we check y = -1 we see that it is not a solution so the answer is y = 4.