Translate the following inference to logic notation: For all x, if x_6 reads a book, then x_6 is a nurse. For all x, if x_6 were a nurse, then x_6 is sad. For all x, if x_6 were sad, then x_6 is writing a letter. For all x, if x_6 writes a letter, then x_6 is reading a book. Therefore for all x, if x_6 writes a letter, then x_6 is sad.
forall x: P(x) -> Q(x). forall x: Q(x) -> R(x). forall x: R(x) -> S(x). forall x: S(x) -> P(x). Therefore forall x: S(x) -> R(x).