Consider the following premises. p_4 or ~p_9. p_9 or ~p_4. Can we infer p_9 -> p_4 from them?
 From p_9 or ~p_4 we can infer p_4 -> p_9. Finally, from p_4 or ~p_9 we can infer p_9 -> p_4. Therefore, the answer is yes.