Consider the following premises. r_4 or p. p_3 <-> p. ~p_3. ~r_4 or r_7. Can we infer ~r_7 from them?
 From r_4 or p, ~r_4 or r_7 we can infer p or r_7. From p_3 <-> p, ~p_3 we can infer ~p. Finally, from p or r_7, ~p we can infer r_7, which contradicts ~r_7. Therefore, the answer is no.