Translate the following inference to logic notation: Linda is a taxi driver if and only if Elisabeth is a server. Linda is not a janitor. Linda is a taxi driver if and only if Linda is a janitor. For all x, x_7 is a server if and only if x_7 will drink water. Therefore Elisabeth is not drinking water.
p <-> P(a). ~q. p <-> q. forall x: P(x) <-> Q(x). Therefore ~Q(a).