Consider the following premises. For all x_6, x_6 will read a book if and only if x_6 will play tennis. For all x_6, x_6 will not write a letter. For all x_6, x_6 will write a letter or x_6 will not play tennis. Can we infer the following from them? For all x_6, x_6 will not read a book.
 From the fact that for all x_6, x_6 will write a letter or x_6 will not play tennis we can infer that for all x_6, if x_6 plays tennis, then x_6 is writing a letter. From the fact that for all x_6, if x_6 plays tennis, then x_6 is writing a letter, and that for all x_6, x_6 will not write a letter we can infer that for all x_6, x_6 will not play tennis. Finally, from the fact that for all x_6, x_6 will read a book if and only if x_6 will play tennis, and that for all x_6, x_6 will not play tennis we can infer that for all x_6, x_6 will not read a book. Therefore, the answer is yes.