Consider the following premises. u -> w. u <-> q_1. w -> q_1. Can we infer q_1 -> u from them? If possible, name the inference rules being used at each step.
 From u -> w, w -> q_1 we can infer u -> q_1 via transitivity. Finally, from u <-> q_1 we can infer q_1 -> u via biconditional elimination. Therefore, the answer is yes.