Translate the following inference to logic notation: For all x, x_7 will work or x_7 will not write a letter. For all x, if x_7 works, then x_7 is writing a letter. For all x, x_7 is not a politician. For all x, if x_7 writes a letter, then x_7 is a politician. Therefore for all x, x_7 will not work.
forall x: P(x) or ~Q(x). forall x: P(x) -> Q(x). forall x: ~R(x). forall x: Q(x) -> R(x). Therefore forall x: ~P(x).