Consider the following premises. t_3 <-> q_2. u or ~q_2. u -> w_2. ~w_2. Can we infer ~t_3 from them? If possible, name the inference rules being used at each step.
 From u -> w_2, ~w_2 we can infer ~u via modus tollens. From u or ~q_2 we can infer q_2 -> u via rewriting. From q_2 -> u, ~u we can infer ~q_2 via modus tollens. Finally, from t_3 <-> q_2, ~q_2 we can infer ~t_3 via biconditional elimination. Therefore, the answer is yes.