One-to-one functions?

Question

Let N be the set of positive integers. Prove that G: N x N --> N given by G(m, n) = 5(to the mth power)7(to the nth power) is one-to-one.

Been looking at this for a while and have yet to come up with anything....thanks for any help!

Answer 1

Here is a hint: Assume that this function is not one to one and show that this leads to a contradiction.