5. Find the closed form solutions of the following recurrence relations with given initial conditions. Use forward substitution or backward substitution as described in Example 10 in the text. (a) an-an-1,00 = 5 (b) anan-1+3, ao = 1 (c) anan-1-n, ao = 4 (d) an = 2nan-1,00 = 3 (e) an-an-1+n-1, ao = 7