Translate the following inference to logic notation: For all x, if x were a taxi driver, then x is an electrician. For all x, if x were an electrician, then x is a taxi driver. For all x, x is an electrician if and only if x is a taxi driver. Therefore for all x, x is an electrician if and only if x is a taxi driver.
forall x: P(x) -> Q(x). forall x: Q(x) -> P(x). forall x: Q(x) <-> P(x). Therefore forall x: Q(x) <-> P(x).