Translate the following inference to logic notation: For all x, x will write a letter or x will not read a book. For all x, x will play squash or x will read a book. There is at least one x for which x will play squash if and only if x will write a letter. Therefore there is at least one x for which x will write a letter.
forall x: P(x) or ~Q(x). forall x: R(x) or Q(x). exists x: R(x) <-> P(x). Therefore exists x: P(x).