Translate the following inference to logic notation: For all x, if x_9 plays squash, then x_9 is a writer. For all x, if x_9 listens to a song, then x_9 is a janitor. For all x, x_9 will listen to a song. For all x, x_9 is a janitor or x_9 is not a writer. Therefore for all x, x_9 is a janitor.
forall x: P(x) -> Q(x). forall x: R(x) -> S(x). forall x: R(x). forall x: S(x) or ~Q(x). Therefore forall x: S(x).