Translate the following inference to logic notation: For all x, x_25 will go running if and only if x_25 is an office clerk. For all x, z_3 will write a letter. For all x, x_25 will go running. Therefore Mary is writing a letter and David is an office clerk.
forall x: P(x) <-> Q(x). forall x: R(x). forall x: P(x). Therefore R(a) and Q(b).