Consider the following premises. r or Q_9(a_5). forall x_9: P_9(x_9) <-> Q_9(x_9). r -> P_9(a_5). Can we infer P_9(a_5) from them? If possible, name the inference rules being used at each step.
 From forall x_9: P_9(x_9) <-> Q_9(x_9) we can infer forall x_9: Q_9(x_9) -> P_9(x_9) via universal biconditional elimination. From forall x_9: Q_9(x_9) -> P_9(x_9) we can infer Q_9(a_5) -> P_9(a_5) via universal instantiation. Finally, from r -> P_9(a_5), Q_9(a_5) -> P_9(a_5), r or Q_9(a_5) we can infer P_9(a_5) via disjunction elimination. Therefore, the answer is yes.