Translate the following inference to logic notation: For all x, x_7 will not write a letter. There is at least one x for which x_7 will go running. For all x, x_7 will write a letter. Therefore there is at least one x for which x_7 will go running.
forall x: ~P(x). exists x: Q(x). forall x: P(x). Therefore exists x: Q(x).