6. Solve the following recurrence equations. a) (8 points) Use the substitution method to show that 7(n) = T(n-1)+2n 0(n?). You can assume T(1) = 2. b) (8 points) Use the iteration method to solve the following recurrence equation (hint: you can assume n!2* = 2 for some integers n and k): 0 if n=2 T(n) = T(In)+1 if n>2 c) (6 points) Use Master method to solve T(n) = 16T(n/4) + n?. d) (8 points) Use Master method to solve T(n) = T(9n/10) +n. = { 2