Translate the following inference to logic notation: For all x, x_6 is a lawyer if and only if x_6 is a soldier. For all x, x_6 will not write a letter. For all x, x_6 will write a letter or x_6 is not a lawyer. Therefore for all x, x_6 is not a soldier.
forall x: P(x) <-> Q(x). forall x: ~R(x). forall x: R(x) or ~P(x). Therefore forall x: ~Q(x).