factor 4x^2-12+9

well it might have been if there was an x next to the 12. :/

(4x-9)(x-1)

Let's look at this one, again....I assume it's really supposed to be

 4x^2-12x+9

This is a perfect square trinomial....the factorization is

(2x - 3) (2x - 3)  = (2x - 3)²