Answer:
y = - 3
Explanation:
Providing you mean (y - 9)/(y + 3) then it is always the variable in the denominator that is going to cause trouble. If it equals zero at any point, it's game over.
It's a little better if you get a result like 0/0. That problem has a "depends" as an answer, but by and large, you don't want to monkey around with 0 in the bottom of a fraction.
y + 3 = 0 Subtract 3 from both sides.
y + 3 - 3 = 0 - 3 Combine
y = - 3