Translate the following inference to logic notation: For all x, z_3 is a server or z_3 will not cook. For all x, z_3 is a server if and only if z_3 will write a letter. Therefore for all x, if z_3 cooks, then z_3 is writing a letter.
forall x: P(x) or ~Q(x). forall x: P(x) <-> R(x). Therefore forall x: Q(x) -> R(x).