Consider the following premises. For all x_8, if x_8 were a politician, then x_8 is playing squash. For all x_8, x_8 is not a politician. For all x_8, x_8 will play squash if and only if x_8 is a politician. There is at least one x_8 for which if x_8 climbs a mountain, then x_8 is playing squash. Can we infer the following from them? If we can, name the inference rule being used: For all x_8, x_8 will climb a mountain.
 From the fact that for all x_8, x_8 will play squash if and only if x_8 is a politician we can infer that for all x_8, if x_8 plays squash, then x_8 is a politician via universal biconditional elimination. From the fact that for all x_8, if x_8 plays squash, then x_8 is a politician, and that for all x_8, if x_8 were a politician, then x_8 is playing squash we can infer that for all x_8, x_8 will play squash if and only if x_8 is a politician via universal biconditional introduction. From the fact that for all x_8, x_8 will play squash if and only if x_8 is a politician, and that for all x_8, x_8 is not a politician we can infer that for all x_8, x_8 will not play squash via universal biconditional elimination. Finally, from the fact that there is at least one x_8 for which if x_8 climbs a mountain, then x_8 is playing squash, and that for all x_8, x_8 will not play squash we can infer that there is at least one x_8 for which x_8 will not climb a mountain via existential modus tollens, which contradicts that For all x_8, x_8 will climb a mountain. Therefore, the answer is no.