Consider the following premises. For all x_6, x_6 will read a book if and only if x_6 will play squash. For all x_6, x_6 is a doctor. For all x_6, if x_6 plays squash, then x_6 is not a doctor. Can we infer the following from them? If we can, name the inference rule being used: For all x_6, x_6 will not read a book.
 From the fact that for all x_6, if x_6 plays squash, then x_6 is not a doctor, and that for all x_6, x_6 is a doctor we can infer that for all x_6, x_6 will not play squash via universal modus tollens. From the fact that for all x_6, x_6 will read a book if and only if x_6 will play squash we can infer that for all x_6, if x_6 reads a book, then x_6 is playing squash via universal biconditional elimination. Finally, from the fact that for all x_6, if x_6 reads a book, then x_6 is playing squash, and that for all x_6, x_6 will not play squash we can infer that for all x_6, x_6 will not read a book via universal modus tollens. Therefore, the answer is yes.