Translate the following inference to logic notation: For all x, x_6 is a writer or x_6 will not drive a car. For all x, if x_6 were a writer, then x_6 is a doctor. For all x, if x_6 were a doctor, then x_6 is driving a car. Therefore for all x, x_6 will drive a car if and only if x_6 is a writer.
forall x: P(x) or ~Q(x). forall x: P(x) -> R(x). forall x: R(x) -> Q(x). Therefore forall x: Q(x) <-> P(x).