Foundations of Algorithms. please answer both of these questions in detail please and thank you

16. Suppose that, in a divide-and-conquer algorithm, we always divide an instance of size n of a problem into 10 subinstances of size n/3, and the dividing and combining steps take a time in (n2). Write a recurrence equation for the running time T(n), and solve the equation for T(n). 21. Show that if W(n)2(p1)(p2)+2(np)(np1)+n1 then W(n)2n(n1)for1pn. This result is used in the discussion of the worst-case time complexity analysis of Algorithm 2.6 (Quicksort)