Consider the following premises. For all x_9, if x_9 were a taxi driver, then x_9 is a police officer. For all x_9, if x_9 reads a book, then x_9 is a taxi driver. For all x_9, x_9 will not work. For all x_9, if x_9 works, then x_9 is a police officer. For all x_9, if x_9 were a police officer, then x_9 is working. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_9 for which x_9 will read a book.
 From the fact that for all x_9, if x_9 were a police officer, then x_9 is working, and that for all x_9, if x_9 works, then x_9 is a police officer we can infer that for all x_9, x_9 is a police officer if and only if x_9 will work via universal biconditional introduction. From the fact that for all x_9, if x_9 reads a book, then x_9 is a taxi driver, and that for all x_9, if x_9 were a taxi driver, then x_9 is a police officer we can infer that for all x_9, if x_9 reads a book, then x_9 is a police officer via universal transitivity. From the fact that for all x_9, x_9 is a police officer if and only if x_9 will work, and that for all x_9, x_9 will not work we can infer that for all x_9, x_9 is not a police officer via universal biconditional elimination. Finally, from the fact that for all x_9, if x_9 reads a book, then x_9 is a police officer, and that for all x_9, x_9 is not a police officer we can infer that for all x_9, x_9 will not read a book via universal modus tollens, which contradicts that There is at least one x_9 for which x_9 will read a book. Therefore, the answer is no.