Consider the following premises. s_4 <-> q_9. ~s_4. s_1 -> q_9. s_1 or ~q_9. Can we infer s_1 from them?
 From s_1 or ~q_9 we can infer q_9 -> s_1. From s_4 <-> q_9, ~s_4 we can infer ~q_9. From s_1 -> q_9, q_9 -> s_1 we can infer s_1 <-> q_9. Finally, from s_1 <-> q_9, ~q_9 we can infer ~s_1, which contradicts s_1. Therefore, the answer is no.