need help with question no 12(b).

need the solution that represents the time complexity of an algorithm like O(n) or O(n.logn)

12. Solve the following recurrence equations using the characteristic equation (a) tn-4tn-1 -3tn- for n>1 to 0 (b) t3tn-1 -2tn-2 + n2 for n >1 to 0 to=0 nce equation giv in Example B.15