Translate the following inference to logic notation: David is not taking a plane. For all x, if x_6 reads a book, then x_6 is playing tennis. For all x, if x_6 plays tennis, then x_6 is taking a plane. Therefore David is not reading a book.
~P(a). forall x: Q(x) -> R(x). forall x: R(x) -> P(x). Therefore ~Q(a).