7. Solve the following recurrences and find the efficiency class for each of them. (10%) 1. A(n) = 3A(n 1) for n > 1, A(1) = 4 2. A(n) = A(n-1) +5 for n > 1, A(1) = 0 1 3. A(n) = A(n-1) + n for n > 0, A0 = 0) 4. A(n) = A(n/5) +1 for n > 1, A(1) = 1 (solve for n = 54)