What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: exists x_9: P_5(x_9) <-> Q(x_9). forall x_9: Q_9(x_9) -> Q(x_9). forall x_9: P_9(x_9) or Q_9(x_9). forall x_9: P_9(x_9) -> Q(x_9).
forall x_9: Q(x_9) can be inferred via the universal disjunction elimination rule. exists x_9: P_5(x_9) -> Q(x_9) can be inferred via the existential biconditional elimination rule. exists x_9: Q(x_9) -> P_5(x_9) can be inferred via the existential biconditional elimination rule.