1. The problem statement, all variables and given/known data Not actually for homework, but i didn't know where to post this. Problem: Show that any integer to the fourth power can be expressed as either 5k or 5k+1 where k is an integer. 2. Relevant equations None. 3. The attempt at a solution My starting point is to consider that all integers can be expressed as either: 2x or 2x+1 taking these to the fourth power I arrive at: 16k or 16k + 1 now i'm stuck, any tips? am i even on the right trail here?