Consider the following premises. ~q_1. t -> q_1. q_1 -> t. Can we infer ~t from them?
 From q_1 -> t, t -> q_1 we can infer q_1 <-> t. From q_1 <-> t we can infer t -> q_1. Finally, from t -> q_1, ~q_1 we can infer ~t. Therefore, the answer is yes.