Consider the following premises. p_7 -> r_1. p_7 or ~q_7. r_3 -> q_7. Can we infer ~(r_3 -> r_1) from them?
 From p_7 or ~q_7 we can infer q_7 -> p_7. From q_7 -> p_7, p_7 -> r_1 we can infer q_7 -> r_1. Finally, from r_3 -> q_7, q_7 -> r_1 we can infer r_3 -> r_1, which contradicts ~(r_3 -> r_1). Therefore, the answer is no.