Consider the following premises. w_3 -> u_2. t_2 -> w_3. t_1. ~u_2. Can we infer ~t_2 from them?
 From w_3 -> u_2, ~u_2 we can infer ~w_3. Finally, from t_2 -> w_3, ~w_3 we can infer ~t_2. Therefore, the answer is yes.