Translate the following inference to logic notation: For all x, x_6 will play squash if and only if x_6 is a sailor. Thomas is not playing squash. For all x, if x_6 were a sailor, then x_6 is playing squash. Therefore Thomas is not a sailor.
forall x: P(x) <-> Q(x). ~P(a). forall x: Q(x) -> P(x). Therefore ~Q(a).