Translate the following inference to logic notation: If David were fast, then Richard is an astronaut. Richard is not an astronaut. If Richard were an astronaut, then David is cooking. For all x, if x_12 cooks, then x_12 is fast. Therefore David is not fast.
P(a) -> p. ~p. p -> Q(a). forall x: Q(x) -> P(x). Therefore ~P(a).