Consider the following premises. p_9 -> r. r -> p_1. p_9 or ~p_1. Can we infer r -> p_9 from them? If possible, name the inference rules being used at each step.
 From p_9 or ~p_1 we can infer p_1 -> p_9 via rewriting. Finally, from r -> p_1, p_1 -> p_9 we can infer r -> p_9 via transitivity. Therefore, the answer is yes.