X & A are counting numbers. This means that a is a number that comes after x just like 2 comes after 1: a > x
Let's assume that x = 1 & a = 2

If x = 2 & a = 3, we have:

If x = 3 & a = 4, we have:

Except for the first scenario where x = 1 & a = 2 where we got x ^(-a) equal to 1, for every other subsequent value, we will obtain values less than 1