Translate the following inference to logic notation: For all x, x_7 will play a game or x_7 is rich. For all x, x_7 is a taxi driver. There is at least one x for which x_7 will not play a game or x_7 is sad. For all x, if x_7 were rich, then x_7 is not a taxi driver. Therefore there is at least one x for which x_7 is sad.
forall x: P(x) or Q(x). forall x: R(x). exists x: ~P(x) or S(x). forall x: Q(x) -> ~R(x). Therefore exists x: S(x).