Translate the following inference to logic notation: For all x, if y drives a car, then y is a taxi driver. For all x, y will drive a car or y is not a taxi driver. Therefore for all x, y is a taxi driver if and only if y will drive a car.
forall x: P(x) -> Q(x). forall x: P(x) or ~Q(x). Therefore forall x: Q(x) <-> P(x).