Translate the following inference to logic notation: It is windy if and only if Robert is drinking water. For all x, x_17 will go running or x_17 will not take a plane. If David goes running, then Robert is drinking water. It is windy or David is taking a plane. Therefore Robert is drinking water.
p <-> q. forall x: P(x) or ~Q(x). P(a) -> q. p or Q(a). Therefore q.