Consider the following premises. ~S_9(a_9) or s. forall x_9: R_9(x_9) or S_9(x_9). ~r_5. ~R_9(a_9) or r_5. Can we infer ~s from them? If possible, name the inference rules being used at each step.
 From forall x_9: R_9(x_9) or S_9(x_9) we can infer R_9(a_9) or S_9(a_9) via universal instantiation. From R_9(a_9) or S_9(a_9), ~R_9(a_9) or r_5 we can infer S_9(a_9) or r_5 via resolution. From S_9(a_9) or r_5, ~S_9(a_9) or s we can infer r_5 or s via resolution. Finally, from r_5 or s, ~r_5 we can infer s via disjunctive syllogism, which contradicts ~s. Therefore, the answer is no.