Consider the following premises. p_2 or ~u. u. q_6 -> p_2. Can we infer ~p_2 from them?
 From u we can infer u or q_6. From p_2 or ~u we can infer u -> p_2. Finally, from u -> p_2, q_6 -> p_2, u or q_6 we can infer p_2, which contradicts ~p_2. Therefore, the answer is no.