Hey all, some help with these proofs would be appreciated:

2^(2k+1) + 1 is divisible by 3

10^k + 3 * 4^(k+2) + 5 is divisible by 9

Power is defined in the following way. Let b be a fixed integer. We define b^k for all integers k >= 0 by:

b^0 := 1

Assuming b^n defined, let b^(n+1) := b^n * b

Thanks!