Translate the following inference to logic notation: For all x, x_7 is an artist or x_7 will not drink water. There is at least one x for which if x_7 were an artist, then x_7 is drinking water. For all x, if x_7 were an artist, then x_7 is drinking water. Therefore there is at least one x for which x_7 is an artist if and only if x_7 will drink water.
forall x: P(x) or ~Q(x). exists x: P(x) -> Q(x). forall x: P(x) -> Q(x). Therefore exists x: P(x) <-> Q(x).