Translate the following inference to logic notation: There is at least one x for which x_7 will make tea. For all x, x_7 will play tennis if and only if x_7 is a cashier. For all x, x_7 will play tennis. Therefore there is at least one x for which x_7 is a cashier and x_7 will make tea.
exists x: P(x). forall x: Q(x) <-> R(x). forall x: Q(x). Therefore exists x: R(x) and P(x).