How to use natural deduction to prove a statement.

Question

Prove the following statements using natural deduction rules (such as conjunction elimination, implication introduction, etc.)

a. [(p ∧ q) ∨ (p ∧ r)] ⊢ [p ∧ (q ∨ r)]

b. [¬p, p ∨ q] ⊢ [q]

c. [¬p ∧ ¬q] ⊢ [¬ (p ∨ q)]

d. [p ∧ q] ⊢ [¬ (¬p ∨ ¬q)]

Answer 1