Translate the following inference to logic notation: For all x, if x_17 were a bartender, then x_17 is reading a book. Patricia is not sad. Patricia is sad if and only if Charles is reading a book. Charles is a bartender or Charles is not reading a book. Therefore Charles is not a bartender.
forall x: P(x) -> Q(x). ~p. p <-> Q(a). P(a) or ~Q(a). Therefore ~P(a).