Consider the following premises. w_2 -> q_9. ~p_9. p_9 <-> q_9. Can we infer w_2 from them? If possible, name the inference rules being used at each step.
 From p_9 <-> q_9 we can infer q_9 -> p_9 via biconditional elimination. From q_9 -> p_9, ~p_9 we can infer ~q_9 via modus tollens. Finally, from w_2 -> q_9, ~q_9 we can infer ~w_2 via modus tollens, which contradicts w_2. Therefore, the answer is no.