Translate the following inference to logic notation: For all x, if x_15 plays squash, then x_15 is a musician. If it is sunny, then Charles is climbing a mountain. Charles is climbing a mountain if and only if Linda is playing squash. Linda is not a musician. Therefore it is not sunny.
forall x: P(x) -> Q(x). p -> q. q <-> P(a). ~Q(a). Therefore ~p.