Translate the following inference to logic notation: For all x, if x_9 writes a letter, then x_9 is an artist. For all x, if x_9 cooks, then x_9 is writing a letter. There is at least one x for which x_9 is a taxi driver if and only if x_9 will cook. Therefore there is at least one x for which if x_9 were a taxi driver, then x_9 is an artist.
forall x: P(x) -> Q(x). forall x: R(x) -> P(x). exists x: S(x) <-> R(x). Therefore exists x: S(x) -> Q(x).