Translate the following inference to logic notation: For all x, if z_2 were a poet, then z_2 is writing a letter. For all x, if z_2 were a bartender, then z_2 is a poet. For all x, if z_2 writes a letter, then z_2 is a bartender. Therefore if David were a bartender, then David is writing a letter.
forall x: P(x) -> Q(x). forall x: R(x) -> P(x). forall x: Q(x) -> R(x). Therefore R(a) -> Q(a).