Consider the following premises. For all x_1, if x_1 works, then x_1 is rich. For all x_1, if x_1 were a soldier, then x_1 is rich. For all x_1, if x_1 were rich, then x_1 is working. Can we infer the following from them? If we can, name the inference rule being used: For all x_1, if x_1 were a soldier, then x_1 is working.
 From the fact that for all x_1, if x_1 works, then x_1 is rich, and that for all x_1, if x_1 were rich, then x_1 is working we can infer that for all x_1, x_1 will work if and only if x_1 is rich via universal biconditional introduction. From the fact that for all x_1, x_1 will work if and only if x_1 is rich we can infer that for all x_1, if x_1 were rich, then x_1 is working via universal biconditional elimination. Finally, from the fact that for all x_1, if x_1 were a soldier, then x_1 is rich, and that for all x_1, if x_1 were rich, then x_1 is working we can infer that for all x_1, if x_1 were a soldier, then x_1 is working via universal transitivity. Therefore, the answer is yes.