This about big-O

Please explain clearly STEP BY STEP . Just want to see a,b k. Please show how you got the answer. Confused on how solving it.

0.1. In each of the following situations, indicate whether f = 0(g), or f = S2(g), or both (in which case f = (g)). f(n) g(n) (a) n - 100 n - 200 (b) n!/2 n2/3 (c) 100n + logn n+ (log n)2 (d) logn 10n log 10n (e) log 2n log 3n (f) 10 log n log(n?) n1.01 nlogn (h) n(log n) (i) 120.1 (log n) 10 6) (log n)logn n/ log n (k) (log n) (1) n1/2 5log (m) 31 (n) 21 2n+1 (0) n! 21 n2 / log n n2n