Consider the following premises. For all x_2, if x_2 takes a plane, then x_2 is playing squash. For all x_2, if x_2 plays tennis, then x_2 is taking a plane. There is at least one x_2 for which if x_2 plays squash, then x_2 is playing tennis. Can we infer the following from them? There is at least one x_2 for which x_2 will play tennis if and only if x_2 will take a plane.
 From the fact that for all x_2, if x_2 takes a plane, then x_2 is playing squash, and that there is at least one x_2 for which if x_2 plays squash, then x_2 is playing tennis we can infer that there is at least one x_2 for which if x_2 takes a plane, then x_2 is playing tennis. Finally, from the fact that for all x_2, if x_2 plays tennis, then x_2 is taking a plane, and that there is at least one x_2 for which if x_2 takes a plane, then x_2 is playing tennis we can infer that there is at least one x_2 for which x_2 will play tennis if and only if x_2 will take a plane. Therefore, the answer is yes.