Translate the following inference to logic notation: Charles is playing tennis if and only if John is working. If John were an electrician, then John is working. For all x, if z works, then z is writing a letter. For all x, if z writes a letter, then z is an electrician. Charles is not playing tennis. Therefore John is not an electrician.
p <-> P(a). Q(a) -> P(a). forall x: P(x) -> R(x). forall x: R(x) -> Q(x). ~p. Therefore ~Q(a).