Translate the following inference to logic notation: For all x, x_6 is a bartender if and only if x_6 is a cashier. For all x, x_6 is not happy or x_6 is a scientist. There is at least one x for which if x_6 were a scientist, then x_6 is a bartender. For all x, x_6 is happy or x_6 is a cashier. Therefore there is at least one x for which x_6 is a bartender.
forall x: P(x) <-> Q(x). forall x: ~R(x) or S(x). exists x: S(x) -> P(x). forall x: R(x) or Q(x). Therefore exists x: P(x).