Consider the following premises. q_3. p_17 <-> s. ~s. p_3 -> ~q_3. Can we infer p_3 from them? If possible, name the inference rules being used at each step.
 From p_17 <-> s, ~s we can infer ~p_17 via biconditional elimination. Finally, from p_3 -> ~q_3, q_3 we can infer ~p_3 via modus tollens, which contradicts p_3. Therefore, the answer is no.