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