Translate the following inference to logic notation: For all x, if x goes running, then x is writing a letter. For all x, x will go running if and only if x will write a letter. Therefore for all x, if x goes running, then x is writing a letter.
forall x: P(x) -> Q(x). forall x: P(x) <-> Q(x). Therefore forall x: P(x) -> Q(x).