Note that even though all of the factors in the numerator were divided
out there is still a 1 in there. It is easy to think there there
is "nothing" left and make the numerator disappear. But when you
divide a factor by itself there is actually a 1 there. Just like
2/2 = 1 or 5/5 = 1.
Note that the values that would be excluded from the domain are 0,
5, -2, and 2. Those are the values that makes the original
denominator of the product equal to 0.