Consider the following premises. q_15 -> u. ~u. q_15 <-> q_7. u -> q_15. Can we infer ~q_7 or s from them?
 From u -> q_15, q_15 -> u we can infer u <-> q_15. From u <-> q_15, ~u we can infer ~q_15. From q_15 <-> q_7, ~q_15 we can infer ~q_7. Finally, from ~q_7 we can infer ~q_7 or s. Therefore, the answer is yes.