Consider the following premises. w_1 <-> q_8. u_1 <-> q_8. ~u_1. Can we infer ~w_1 from them? If possible, name the inference rules being used at each step.
 From u_1 <-> q_8, ~u_1 we can infer ~q_8 via biconditional elimination. From w_1 <-> q_8 we can infer w_1 -> q_8 via biconditional elimination. Finally, from w_1 -> q_8, ~q_8 we can infer ~w_1 via modus tollens. Therefore, the answer is yes.