Hello, I am having a hard time understanding whyk(k - 1)^n - (k - 1)^n - (-1)^n(k - 1) = (k - 1)^(n+1) + (-1)^(n+1) (k - 1).

What i specifically don't get is how to get from ^n to ^n+1. I would appreciate it if someone could tell me how this is done.