Consider the following premises. q_3 -> p_8. u -> r. r -> q_3. p_8 -> u. ~r. Can we infer ~p_8 from them?
 From p_8 -> u, u -> r we can infer p_8 -> r. From r -> q_3, q_3 -> p_8 we can infer r -> p_8. From r -> p_8, p_8 -> r we can infer r <-> p_8. Finally, from r <-> p_8, ~r we can infer ~p_8. Therefore, the answer is yes.