Prove using induction

Prove using induction: n^3 + 2n is divisible by 3 for all n > 0. Let F(n) be the Fibonacci sequence. Prove using induction: sigma_i = 1^n F(i) = F(n + 2) - 1 for all n > 0. (The sum of the first n Fibonacci numbers is equal to F(n + 2) - 1. Use F(1) = F(2) = 1.)