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