lets start over with this problem:

Question

n^2 - 9n + 9

how do you determine if this is a perfect square, and can you factor it?

Answer 1

I posted two answers below the two you got.

n^2 - 9 n + 81/4 = (n-9/2)^2

would be a perfect square

n^2 - 6 n + 9 = (n-3)^2

would be a perfect square

You can not factor n^2 - 9 n + 9