Automata and grammars

Prove that any context-free grammar can be converted (except for λ) to an equivalent grammar with rules of the following type only, where a, b ∈ T and W ∈ V.

(a) A → a
(b) A→aWb


or


Prove that any context-free grammar can be converted (except for λ) by an equivalent grammar with rules of the following type only, where a ∈ T and A,B,C ∈ V.

(a) A→ a
(b) A→ aB
(c) A→ aBC