Consider the following premises. For all x_9, if x_9 plays squash, then x_9 is cooking. For all x_9, if x_9 were sad, then x_9 is cooking. For all x_9, x_9 will play squash if and only if x_9 is a cashier. For all x_9, if x_9 cooks, then x_9 is playing squash. For all x_9, x_9 is not a cashier. Can we infer the following from them? For all x_9, x_9 is not sad.
 From the fact that for all x_9, if x_9 plays squash, then x_9 is cooking, and that for all x_9, if x_9 cooks, then x_9 is playing squash we can infer that for all x_9, x_9 will play squash if and only if x_9 will cook. From the fact that for all x_9, x_9 will play squash if and only if x_9 is a cashier, and that for all x_9, x_9 is not a cashier we can infer that for all x_9, x_9 will not play squash. From the fact that for all x_9, x_9 will play squash if and only if x_9 will cook, and that for all x_9, x_9 will not play squash we can infer that for all x_9, x_9 will not cook. Finally, from the fact that for all x_9, if x_9 were sad, then x_9 is cooking, and that for all x_9, x_9 will not cook we can infer that for all x_9, x_9 is not sad. Therefore, the answer is yes.