Consider the following premises. r <-> s_2. q_3 <-> r. s_2 or q_3. Can we infer r from them?
 From q_3 <-> r we can infer q_3 -> r. From r <-> s_2 we can infer s_2 -> r. Finally, from s_2 -> r, q_3 -> r, s_2 or q_3 we can infer r. Therefore, the answer is yes.