Translate the following inference to logic notation: For all x, if x_8 were a taxi driver, then x_8 is listening to a song. For all x, if x_8 listens to a song, then x_8 is a taxi driver. For all x, if x_8 listens to a song, then x_8 is a taxi driver. Therefore if Susan were a taxi driver, then Susan is listening to a song.
forall x: P(x) -> Q(x). forall x: Q(x) -> P(x). forall x: Q(x) -> P(x). Therefore P(a) -> Q(a).