Let A,B,C be integers such that A^2 + B^2 = C^2. Prove at least one of A and B is even.

Please help guide me through this problem so I can understand it better thanks.

I have another question also

let a and b be positive such that a^2 = b^3

given 4 divides b, prove that 8 divides a

Im hoping if someone can guide me through this problem also thanks.