Consider the following premises. Sarah is sleeping or Sarah is not driving a car. For all y, if y sleeps, then y is driving a car. Can we infer the following from them? If we can, name the inference rule being used: Sarah is sleeping if and only if Sarah is driving a car.
 From the fact that for all y, if y sleeps, then y is driving a car we can infer that if Sarah sleeps, then Sarah is driving a car via universal instantiation. From the fact that Sarah is sleeping or Sarah is not driving a car we can infer that if Sarah drives a car, then Sarah is sleeping via rewriting. Finally, from the fact that if Sarah sleeps, then Sarah is driving a car, and that if Sarah drives a car, then Sarah is sleeping we can infer that Sarah is sleeping if and only if Sarah is driving a car via biconditional introduction. Therefore, the answer is yes.