Consider the following premises. forall x_8: P_8(x_8) <-> Q_8(x_8). u_1 -> P_8(a_5). Can we infer u_1 -> Q_8(a_5) from them? If possible, name the inference rules being used at each step.
 From forall x_8: P_8(x_8) <-> Q_8(x_8) we can infer forall x_8: P_8(x_8) -> Q_8(x_8) via universal biconditional elimination. From forall x_8: P_8(x_8) -> Q_8(x_8) we can infer P_8(a_5) -> Q_8(a_5) via universal instantiation. Finally, from u_1 -> P_8(a_5), P_8(a_5) -> Q_8(a_5) we can infer u_1 -> Q_8(a_5) via transitivity. Therefore, the answer is yes.