pls explain this

3.1.5. Co nsider the context-free grammar G = (V, ' R,S), where V = {a, b, S, A, B), = {a, b), Aas, (a) Show that ababba E L(G) (b) Prove that L(G) is the set of all nonempty strings in [a, b] that have equal numbers of occurrences of a and b