Factor out the greatest common factor from the expression 9x^y^4+7x^6y^3-12x^4y^3

Question

I just do not understand how to do this problem. I do know that the greatest common factor for 9 and -12 is 3 but where I get lost at is trying to find a common factor for 7 that I can use 3 to = 7 can someone please help me. This is due tonight at 10:00 my time and 12EST so if you can please help me

Answer 1

There's a part missing.  We can't solve this without that part.

9x^?y^4 + 7x^6y^3 - 12x^4y^3

We need to know what should be in place of the ?.