Translate the following inference to logic notation: If David were a police officer, then Susan is cooking. For all x, if y plays tennis, then y is cooking. For all x, if y cooks, then y is playing tennis. Susan is playing tennis or David is a police officer. Therefore Susan is cooking.
p -> P(a). forall x: Q(x) -> P(x). forall x: P(x) -> Q(x). Q(a) or p. Therefore P(a).