Consider the following premises. ~t_2. ~t_4 <-> q_3. t_4 <-> t_2. Can we infer q_3 from them?
 From t_4 <-> t_2, ~t_2 we can infer ~t_4. From ~t_4 <-> q_3 we can infer ~t_4 -> q_3. Finally, from ~t_4 -> q_3, ~t_4 we can infer q_3. Therefore, the answer is yes.