Consider the following premises. u_3. forall x_17: P_17(x_17) or Q_11(x_17). forall x_17: P_17(x_17) <-> Q_17(x_17). forall x_17: ~Q_17(x_17). Can we infer Q_11(a_9) and u_3 from them? If possible, name the inference rules being used at each step.
 From forall x_17: P_17(x_17) <-> Q_17(x_17), forall x_17: ~Q_17(x_17) we can infer forall x_17: ~P_17(x_17) via universal biconditional elimination. From forall x_17: P_17(x_17) or Q_11(x_17), forall x_17: ~P_17(x_17) we can infer forall x_17: Q_11(x_17) via universal disjunctive syllogism. From forall x_17: Q_11(x_17) we can infer Q_11(a_9) via universal instantiation. Finally, from Q_11(a_9), u_3 we can infer Q_11(a_9) and u_3 via conjunction. Therefore, the answer is yes.