Consider the following premises. ~q. t_3 <-> q_8. q <-> q_8. Can we infer ~t_3 from them?
 From q <-> q_8, ~q we can infer ~q_8. From t_3 <-> q_8 we can infer t_3 -> q_8. Finally, from t_3 -> q_8, ~q_8 we can infer ~t_3. Therefore, the answer is yes.