Consider the following premises. For all x, x is a janitor if and only if x is bored. For all x, if x were a janitor, then x is bored. Can we infer the following from them? If we can, name the inference rule being used: For all x, if x were bored, then x is a janitor.
We can infer this via the universal biconditional elimination rule. Therefore, the answer is yes.