I need help doing problems (a-e)

Use closure under union to show that the following languages are context- free. (a) {a^m b^m: m notequalto n} (b) {a, b}* - {a^n b^n: n greaterthanorequalto 0} (c) {a^m b^n c^p d^q: n = q, or m lessthanorequalto p or m + n = p + q} (d) {a, b}* - L, where L is the language L = {babaabaaab ... ba^n-1 ba^n b: n greaterthanorequalto 1} (e) {w elementof {a, b}*: w = w^R}