Proofs: Construct proofs to show that the following symbolic arguments are valid. Commas mark the breaks between premises, ‘ ∴ ’ precedes the conclusion. You may use the following rules: MP, MT, DS,...

Proofs: Construct proofs to show that the following symbolic arguments are valid.  Commas mark the breaks between premises, ‘∴’ precedes the conclusion. You may use the following rules: MP, MT, DS, HS, CD, Simp, Conj, Add, DeM, DN, Com, As, Cont

∼Y ∨ N, (Y • ∼N) ∨ (Y • Z), (Z • Y) → ∼∼U ∴ U ∨ ∼V