Consider the following premises. p_1 or r. p_7 <-> q_7. ~p_1. ~p_7. Can we infer q_7 from them? If possible, name the inference rules being used at each step.
 From p_1 or r, ~p_1 we can infer r via disjunctive syllogism. Finally, from p_7 <-> q_7, ~p_7 we can infer ~q_7 via biconditional elimination, which contradicts q_7. Therefore, the answer is no.