Translate the following inference to logic notation: For all x, if x_6 drives a car, then x_6 is a writer. There is at least one x for which if x_6 were a police officer, then x_6 is driving a car. For all x, if x_6 were a police officer, then x_6 is driving a car. For all x, if x_6 were a writer, then x_6 is a police officer. Therefore there is at least one x for which x_6 will drive a car if and only if x_6 is a police officer.
forall x: P(x) -> Q(x). exists x: R(x) -> P(x). forall x: R(x) -> P(x). forall x: Q(x) -> R(x). Therefore exists x: P(x) <-> R(x).