Hi there all, I have a question that I sincerely don't know how to solve and so would like to discuss it with you guys for any possible solutions. Here's the problem: I need to prove by induction that n5－n is divisible by 30. I start by proving P(1) is true, that is, 15－1=0=30k where k=0. This shows that P(1) is divisible by 30 so it's true. Next, I assume that P(n－1) is true and use this assumption to prove that P(n) is true. I wrote: P(n－1) => (n－1)5－(n－1) = 30k (n－1)*[(n－1)5－1] = 30k Then I had no idea what to do next. I know at the end I have to prove that P(n－1) is a multiple of 30, but how should I prove that by induction? Can anyone help me with this please!!