Translate the following inference to logic notation: For all x, x_5 will climb a mountain if and only if x_5 will read a book. For all x, if x_5 climbs a mountain, then x_5 is reading a book. There is at least one x for which x_5 will not read a book. Therefore there is at least one x for which x_5 will not climb a mountain.
forall x: P(x) <-> Q(x). forall x: P(x) -> Q(x). exists x: ~Q(x). Therefore exists x: ~P(x).