Translate the following inference to logic notation: For all x, x_11 is a server if and only if x_11 is a writer. For all x, x_11 is an office clerk if and only if x_11 is a server. For all x, x_11 is a writer or x_11 is a doctor. For all x, if x_11 were a doctor, then x_11 is an office clerk. Therefore for all x, x_11 is a server.
forall x: P(x) <-> Q(x). forall x: R(x) <-> P(x). forall x: Q(x) or S(x). forall x: S(x) -> R(x). Therefore forall x: P(x).