If i could add more to my last post.. I said that there must be a variable and a constant in order for it to be a difference of two squares but that isnt entirely true. There can also be no constant. For example, x^6-y^2 we end up with (x^3-y)(x^3+y). Even though there was no constant term it is still a difference of squares. this can be expressed as a^2-b^2=(a+b)(a-b).. Sorry if this didnt make sense.. I shouldn't be trying to write this at 2:30 a.m. Well, GOodluck!