Consider the following premises. For all x_9, x_9 will play squash or x_9 will drive a car. There is at least one x_9 for which x_9 will play tennis if and only if x_9 will play squash. For all x_9, x_9 will play tennis or x_9 will not drive a car. Can we infer the following from them? If we can, name the inference rule being used: For all x_9, x_9 will not play tennis.
 From the fact that there is at least one x_9 for which x_9 will play tennis if and only if x_9 will play squash we can infer that there is at least one x_9 for which if x_9 plays squash, then x_9 is playing tennis via existential biconditional elimination. From the fact that for all x_9, x_9 will play tennis or x_9 will not drive a car we can infer that for all x_9, if x_9 drives a car, then x_9 is playing tennis via universal rewriting. Finally, from the fact that there is at least one x_9 for which if x_9 plays squash, then x_9 is playing tennis, that for all x_9, if x_9 drives a car, then x_9 is playing tennis, and that for all x_9, x_9 will play squash or x_9 will drive a car we can infer that there is at least one x_9 for which x_9 will play tennis via existential disjunction elimination, which contradicts that For all x_9, x_9 will not play tennis. Therefore, the answer is no.