Consider the following premises. p_9 <-> t. r_4 <-> t. p_9 <-> q. ~q. Can we infer r_4 from them?
 From p_9 <-> q, ~q we can infer ~p_9. From p_9 <-> t, ~p_9 we can infer ~t. Finally, from r_4 <-> t, ~t we can infer ~r_4, which contradicts r_4. Therefore, the answer is no.