please do not copy past another solution from somewhere else, Please solve a, d, e and f (because cheggs rules say you can answer 4 parts only)

Find regular expressions not nfa

Note that in questions below na(w) and no(w) indicate the number of a's and the number of b's in string w. 1. Find a regular expression for the following languages over S = {a,b}* (a) {w: w does not contain substring bbb} (b) {w: w contains exactly three a's and it ends with abb} (c) {w: na(w) mod 3 = 0 and w begins with ab} (d) {w: (na(w) + n(w)) mod 3 > 2} (e) {w: w mod 2 = 0} (f) L = {a"b" :mn > 4}