Consider the following premises. u_2 <-> q_9. r_2 -> q_9. q or q_5. ~q or u_2. ~q_5 or r_2. Can we infer q_9 from them? If possible, name the inference rules being used at each step.
 From u_2 <-> q_9 we can infer u_2 -> q_9 via biconditional elimination. From q or q_5, ~q or u_2 we can infer q_5 or u_2 via resolution. From q_5 or u_2, ~q_5 or r_2 we can infer u_2 or r_2 via resolution. Finally, from u_2 -> q_9, r_2 -> q_9, u_2 or r_2 we can infer q_9 via disjunction elimination. Therefore, the answer is yes.