Consider the following premises. w <-> q_7. ~p_12. p_12 <-> w. Can we infer ~q_7 or t_3 from them? If possible, name the inference rules being used at each step.
 From p_12 <-> w, ~p_12 we can infer ~w via biconditional elimination. From w <-> q_7, ~w we can infer ~q_7 via biconditional elimination. Finally, from ~q_7 we can infer ~q_7 or t_3 via addition. Therefore, the answer is yes.