Translate the following inference to logic notation: There is at least one x for which if z_4 makes tea, then z_4 is sad. For all x, if z_4 were sad, then z_4 is making tea. For all x, if z_4 makes tea, then z_4 is sad. Therefore there is at least one x for which if z_4 were sad, then z_4 is making tea.
exists x: P(x) -> Q(x). forall x: Q(x) -> P(x). forall x: P(x) -> Q(x). Therefore exists x: Q(x) -> P(x).