Translate the following inference to logic notation: There is at least one x for which x_13 is a mechanic. For all x, x_13 will make tea. For all x, x_13 will play tennis if and only if x_13 is a mechanic. Therefore there is at least one x for which x_13 will play tennis and x_13 will make tea.
exists x: P(x). forall x: Q(x). forall x: R(x) <-> P(x). Therefore exists x: R(x) and Q(x).