(А ↔ B) ∨ ¬(A → (B ∨ C))=(¬А¬B∨AB) ∨ ¬(¬A ∨ B ∨ C) =¬А¬B∨AB ∨ A¬B¬C=

=¬А¬B∨A(B ∨ ¬B¬C)= ¬А¬B∨A(B ∨ ¬C) =¬А¬B∨AB ∨ A¬C