Consider the following premises. u_3 <-> q_7. ~u_3. r. Can we infer r and ~q_7 from them? If possible, name the inference rules being used at each step.
 From u_3 <-> q_7, ~u_3 we can infer ~q_7 via biconditional elimination. Finally, from r, ~q_7 we can infer r and ~q_7 via conjunction. Therefore, the answer is yes.