Translate the following inference to logic notation: For all x, x_9 will work. For all x, if x_9 makes tea, then x_9 is working. For all x, x_9 will make tea if and only if x_9 will work. Therefore for all x, x_9 will make tea.
forall x: P(x). forall x: Q(x) -> P(x). forall x: Q(x) <-> P(x). Therefore forall x: Q(x).