Could some please help me with the following problem,

1. Let n be an integer >1, and suppose that p= (2^n)+1 is a prime. Show that 3^((p-1)/2) + 1 is divisible by p.

I know that im supposed to prove that n is an even number first..but how? and after i ve done that, wat am i supposed to do?

2. if p= 2^n +1, n>1, 3^((p-1)/2) = -1 (mod p), show p is a prime.

thank you so much.