Consider the following premises. If Patricia sleeps, then Sarah is not listening to a song. Patricia is sleeping if and only if Linda is working. For all x_14, x_14 will listen to a song. Can we infer the following from them? If we can, name the inference rule being used: Linda is not working.
 From the fact that for all x_14, x_14 will listen to a song we can infer that Sarah is listening to a song via universal instantiation. From the fact that if Patricia sleeps, then Sarah is not listening to a song, and that Sarah is listening to a song we can infer that Patricia is not sleeping via modus tollens. Finally, from the fact that Patricia is sleeping if and only if Linda is working, and that Patricia is not sleeping we can infer that Linda is not working via biconditional elimination. Therefore, the answer is yes.