Translate the following inference to logic notation: For all x, x_4 is a bartender if and only if x_4 will drive a car. For all x, if x_4 were a bartender, then x_4 is driving a car. Therefore for all x, x_4 will drive a car if and only if x_4 is a bartender.
forall x: P(x) <-> Q(x). forall x: P(x) -> Q(x). Therefore forall x: Q(x) <-> P(x).