Consider the following premises. forall x_1: ~Q_3(x_1). u <-> Q_3(i). ~u -> t. Can we infer t from them?
 From forall x_1: ~Q_3(x_1) we can infer ~Q_3(i). From u <-> Q_3(i), ~Q_3(i) we can infer ~u. Finally, from ~u -> t, ~u we can infer t. Therefore, the answer is yes.