Consider the following premises. For all x_5, if x_5 were a musician, then x_5 is a politician. For all x_5, if x_5 were a politician, then x_5 is a musician. For all x_5, x_5 is a politician or x_5 is an electrician. For all x_5, x_5 is not a musician. Can we infer the following from them? If we can, name the inference rule being used: For all x_5, x_5 is an electrician.
 From the fact that for all x_5, if x_5 were a politician, then x_5 is a musician, and that for all x_5, if x_5 were a musician, then x_5 is a politician we can infer that for all x_5, x_5 is a politician if and only if x_5 is a musician via universal biconditional introduction. From the fact that for all x_5, x_5 is a politician if and only if x_5 is a musician, and that for all x_5, x_5 is not a musician we can infer that for all x_5, x_5 is not a politician via universal biconditional elimination. Finally, from the fact that for all x_5, x_5 is a politician or x_5 is an electrician, and that for all x_5, x_5 is not a politician we can infer that for all x_5, x_5 is an electrician via universal disjunctive syllogism. Therefore, the answer is yes.