Translate the following inference to logic notation: Barbara is a soldier if and only if it is windy. For all x, x_9 is not a nurse. For all x, x_9 is a soldier if and only if x_9 is a nurse. Therefore it is not windy.
P(a) <-> p. forall x: ~Q(x). forall x: P(x) <-> Q(x). Therefore ~p.