Please give a clear answer.

8. (4 pts) Prove that of f-O(h) and g Oh), then ftg oh) You want to begin with the definition of big-O notation: "x(n) is O(y(n)) if there exist constants c0 and no 2 0 so that for all n2no, we have x(n) S c y(n). (ii) Prove or disprove (i.e., with a counter-example): n:(n+5na5