Translate the following inference to logic notation: If it snows, then Linda is taking a plane. For all x, if x_17 takes a plane, then x_17 is a soldier. Linda is a soldier if and only if it is snowing. Therefore if Linda were a soldier, then Linda is taking a plane.
p -> P(a). forall x: P(x) -> Q(x). Q(a) <-> p. Therefore Q(a) -> P(a).