How do I find the y value for which the following problem is undefined?

Question

(4y^3-8y)/(y^2-2y)

Answer 1

Find the y values for which the denominator is zero. There are two of them, 0 and 2

Actually, the fraction is well behaved even in the limiting cases, because

(4y^3-8y)/(y^2-2y) = 4y

Answer 2

thanks, that helped a lot!!