Consider the following premises. For all y_4, y_4 will play squash if and only if y_4 will go running. For all y_4, y_4 will not go running. Can we infer the following from them? If we can, name the inference rule being used: For all y_4, y_4 will not play squash.
We can infer this via the universal biconditional elimination rule. Therefore, the answer is yes.