Translate the following inference to logic notation: For all x, if z_4 drinks water, then z_4 is playing tennis. For all x, z_4 will play tennis if and only if z_4 will drink water. Therefore for all x, if z_4 plays tennis, then z_4 is drinking water.
forall x: P(x) -> Q(x). forall x: Q(x) <-> P(x). Therefore forall x: Q(x) -> P(x).