Translate the following inference to logic notation: For all x, y_1 will drink water if and only if y_1 will play a game. Richard is running if and only if Linda is working. Linda is not working. If Sarah plays a game, then Richard is running. Therefore Sarah is not drinking water.
forall x: P(x) <-> Q(x). p <-> q. ~q. Q(a) -> p. Therefore ~P(a).