Translate the following inference to logic notation: If Charles plays squash, then Mary is listening to a song. For all x, x_7 is a doctor if and only if x_7 will play squash. If Mary listens to a song, then it is late. It is not late. Therefore Charles is not a doctor.
P(a) -> p. forall x: Q(x) <-> P(x). p -> q. ~q. Therefore ~Q(a).