Prove that for all integers a and b and for all natural numbers n, a - b divides an - bn. Note

that zyBooks' definition of x | y requires that a be non-zero. However, this requirement is often

not included in other textbooks. We will use this looser definition of divides and allow to be 0.

We also will define 0º = 1 in this context, though note that in some areas of math 0º is treated as

undefined.