Consider the following premises. s. q <-> q_3. ~q. q_3 or w. Can we infer s and w from them? If possible, name the inference rules being used at each step.
 From q <-> q_3, ~q we can infer ~q_3 via biconditional elimination. From q_3 or w, ~q_3 we can infer w via disjunctive syllogism. Finally, from s, w we can infer s and w via conjunction. Therefore, the answer is yes.