Translate the following inference to logic notation: For all x, x_3 is a writer or x_3 is not a mechanic. For all x, x_3 is a mechanic or x_3 is not a writer. There is at least one x for which x_3 is not a mechanic. Therefore there is at least one x for which x_3 is not a writer.
forall x: P(x) or ~Q(x). forall x: Q(x) or ~P(x). exists x: ~Q(x). Therefore exists x: ~P(x).