Translate the following inference to logic notation: For all x, z will take a plane. For all x, x_18 will not work. For all x, x_18 will play squash if and only if x_18 will work. For all x, x_18 will play squash or z will sleep. Therefore there is at least one x for which z will sleep and z will take a plane.
forall x: P(x). forall x: ~Q(x). forall x: R(x) <-> Q(x). forall x: R(x) or S(x). Therefore exists x: S(x) and P(x).