Translate the following inference to logic notation: For all x, x_12 will sleep if and only if x_12 will play squash. Robert is not listening to a song. For all x, if x_12 plays squash, then x_12 is listening to a song. Therefore Robert is not sleeping.
forall x: P(x) <-> Q(x). ~R(a). forall x: Q(x) -> R(x). Therefore ~P(a).