Consider the following premises. u -> q. p_3. p_3 <-> u. Can we infer q from them? If possible, name the inference rules being used at each step.
 From p_3 <-> u we can infer p_3 -> u via biconditional elimination. From p_3 -> u, p_3 we can infer u via modus ponens. Finally, from u -> q, u we can infer q via modus ponens. Therefore, the answer is yes.