Translate the following inference to logic notation: For all x, if x_5 takes a plane, then x_5 is making tea. For all x, if x_5 makes tea, then x_5 is sad. For all x, x_5 is sad or x_5 will not read a book. There is at least one x for which x_5 will take a plane or x_5 will read a book. Therefore there is at least one x for which x_5 is sad.
forall x: P(x) -> Q(x). forall x: Q(x) -> R(x). forall x: R(x) or ~S(x). exists x: P(x) or S(x). Therefore exists x: R(x).