Consider the following premises. q_3 <-> p. ~q_9. p_9 <-> q_3. p_9 <-> q_9. Can we infer ~p from them? If possible, name the inference rules being used at each step.
 From p_9 <-> q_9, ~q_9 we can infer ~p_9 via biconditional elimination. From p_9 <-> q_3, ~p_9 we can infer ~q_3 via biconditional elimination. Finally, from q_3 <-> p, ~q_3 we can infer ~p via biconditional elimination. Therefore, the answer is yes.