Translate the following inference to logic notation: There is at least one x for which x_12 will read a book or x_12 will play squash. For all x, x_12 will play squash if and only if x_12 will write a letter. For all x, x_12 will not read a book. Therefore there is at least one x for which x_12 will write a letter.
exists x: P(x) or Q(x). forall x: Q(x) <-> R(x). forall x: ~P(x). Therefore exists x: R(x).