The function f(n) = 3f(n-2) + 2f(n-1), where f(2) = 3 and f(1) = -1. What is the value of f(5)?
f(3) = 3f(1) + 2f(2) = 3(-1) + 2(3) = 3
f(4) = 3f(2) + 2f(3) = 3(3) + 2(3) = 15
f(5) = 3f(3) + 2f(4) = 3(3) + 2(15) = 39
