Consider the following premises. t or ~q_7. s -> r_1. s <-> t. Can we infer q_7 -> r_1 from them?
 From s <-> t we can infer t -> s. From t or ~q_7 we can infer q_7 -> t. From t -> s, s -> r_1 we can infer t -> r_1. Finally, from q_7 -> t, t -> r_1 we can infer q_7 -> r_1. Therefore, the answer is yes.