Translate the following inference to logic notation: For all x, if x_17 were sad, then x_17 is climbing a mountain. If Jennifer were a writer, then John is sad. John is climbing a mountain if and only if Jennifer is a writer. Therefore if John were sad, then Jennifer is a writer.
forall x: P(x) -> Q(x). p -> P(a). Q(a) <-> p. Therefore P(a) -> p.