Consider the following premises. w or q_7. t <-> q_7. t <-> q. ~q. ~w or u. Can we infer u from them?
 From t <-> q, ~q we can infer ~t. From w or q_7, ~w or u we can infer q_7 or u. From t <-> q_7, ~t we can infer ~q_7. Finally, from q_7 or u, ~q_7 we can infer u. Therefore, the answer is yes.