Translate the following inference to logic notation: For all x, y is a taxi driver if and only if y will play a game. For all x, if y were a taxi driver, then y is driving a car. For all x, if y drives a car, then y is a taxi driver. There is at least one x for which y will not play a game. Therefore there is at least one x for which y will not drive a car.
forall x: P(x) <-> Q(x). forall x: P(x) -> R(x). forall x: R(x) -> P(x). exists x: ~Q(x). Therefore exists x: ~R(x).