Consider the following premises. q_17 <-> t. t_2 <-> q_17. ~t_2. Can we infer t from them? If possible, name the inference rules being used at each step.
 From t_2 <-> q_17, ~t_2 we can infer ~q_17 via biconditional elimination. From q_17 <-> t we can infer t -> q_17 via biconditional elimination. Finally, from t -> q_17, ~q_17 we can infer ~t via modus tollens, which contradicts t. Therefore, the answer is no.