1) find the explicit rule of: {-2, 5, 24, 61, 122, 213,...}
2) find the explicit rule of {6, 12, 24, 48, 96, 192,...}
3) find the recursive rule of {2, 3, 6, 18,. 108,...}
4) find the recursive rule of f(n) = 5^n + 5
5) find recursive rule of f(n) = 1/n
