Translate the following inference to logic notation: For all x, x_7 is a mechanic if and only if x_7 will play squash. For all x, x_7 is a mechanic or x_7 will climb a mountain. For all x, if x_7 climbs a mountain, then x_7 is playing squash. For all x, if x_7 plays squash, then x_7 is a lawyer. Therefore for all x, x_7 is a lawyer.
forall x: P(x) <-> Q(x). forall x: P(x) or R(x). forall x: R(x) -> Q(x). forall x: Q(x) -> S(x). Therefore forall x: S(x).