Translate the following inference to logic notation: David is playing tennis if and only if Michael is drinking water. For all x, x_10 will cook or x_10 will play tennis. For all x, x_10 will not cook or x_10 will write a letter. If David writes a letter, then Michael is drinking water. Therefore Michael is drinking water.
P(a) <-> p. forall x: Q(x) or P(x). forall x: ~Q(x) or R(x). R(a) -> p. Therefore p.