Translate the following inference to logic notation: For all x, x_9 will drive a car or x_9 is not sad. For all x, if x_9 plays a game, then x_9 is sad. For all x, if x_9 drives a car, then x_9 is playing a game. Therefore if Mary plays a game, then Mary is sad.
forall x: P(x) or ~Q(x). forall x: R(x) -> Q(x). forall x: P(x) -> R(x). Therefore R(a) -> Q(a).