Translate the following inference to logic notation: For all x, x_7 will not take a plane. For all x, x_7 will drink water if and only if x_7 will work. For all x, if x_7 works, then x_7 is a janitor. For all x, x_7 will take a plane if and only if x_7 is a janitor. Therefore for all x, x_7 will not drink water.
forall x: ~P(x). forall x: Q(x) <-> R(x). forall x: R(x) -> S(x). forall x: P(x) <-> S(x). Therefore forall x: ~Q(x).