Translate the following inference to logic notation: For all x, if x_3 cooks, then x_3 is playing squash. For all x, x_3 is excited or x_3 will cook. For all x, x_3 is excited if and only if x_3 will play squash. Therefore for all x, x_3 will play squash.
forall x: P(x) -> Q(x). forall x: R(x) or P(x). forall x: R(x) <-> Q(x). Therefore forall x: Q(x).