Consider the following premises. For all x_8, x_8 will play squash if and only if x_8 is a writer. For all x_8, x_8 will write a letter. For all x_8, x_8 will play squash or x_8 is a janitor. For all x_8, x_8 is not a writer. Can we infer the following from them? There is at least one x_8 for which either x_8 is a janitor or x_8 will write a letter are not true.
 From the fact that for all x_8, x_8 will play squash if and only if x_8 is a writer, and that for all x_8, x_8 is not a writer we can infer that for all x_8, x_8 will not play squash. From the fact that for all x_8, x_8 will play squash or x_8 is a janitor, and that for all x_8, x_8 will not play squash we can infer that for all x_8, x_8 is a janitor. Finally, from the fact that for all x_8, x_8 is a janitor, and that for all x_8, x_8 will write a letter we can infer that for all x_8, x_8 is a janitor and x_8 will write a letter, which contradicts that There is at least one x_8 for which either x_8 is a janitor or x_8 will write a letter are not true. Therefore, the answer is no.