Translate the following inference to logic notation: For all x, x_9 is rich. For all x, x_9 is a taxi driver if and only if x_9 is an artist. For all x, x_9 is not rich. Therefore for all x, x_9 is a taxi driver.
forall x: P(x). forall x: Q(x) <-> R(x). forall x: ~P(x). Therefore forall x: Q(x).