Translate the following inference to logic notation: For all x, x_9 is a taxi driver or x_9 is a scientist. For all x, if x_9 were a mechanic, then x_9 is making tea. There is at least one x for which x_9 is a taxi driver if and only if x_9 is a mechanic. For all x, if x_9 were a scientist, then x_9 is making tea. Therefore there is at least one x for which x_9 will make tea.
forall x: P(x) or Q(x). forall x: R(x) -> S(x). exists x: P(x) <-> R(x). forall x: Q(x) -> S(x). Therefore exists x: S(x).