Translate the following inference to logic notation: For all x, x_3 will play squash if and only if x_3 will take a plane. There is at least one x for which if x_3 takes a plane, then x_3 is writing a letter. Therefore there is at least one x for which if x_3 plays squash, then x_3 is writing a letter.
forall x: P(x) <-> Q(x). exists x: Q(x) -> R(x). Therefore exists x: P(x) -> R(x).