Consider the following premises. ~u_4. t. u_4 <-> q_12. r -> q_12. Can we infer ~r and t from them?
 From u_4 <-> q_12, ~u_4 we can infer ~q_12. From r -> q_12, ~q_12 we can infer ~r. Finally, from ~r, t we can infer ~r and t. Therefore, the answer is yes.