Consider the following premises. ~q. w. w -> p_12. p_12 <-> q. Can we infer q_6 from them?
 From p_12 <-> q, ~q we can infer ~p_12. From w we can infer w or q_6. From w -> p_12, ~p_12 we can infer ~w. Finally, from w or q_6, ~w we can infer q_6. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.