Consider the following premises. For all x_8, x_8 is fast if and only if x_8 is excited. For all x_8, x_8 is fast. For all x_8, x_8 is a nurse. Can we infer the following from them? If we can, name the inference rule being used: For all x_8, x_8 is excited.
 From the fact that for all x_8, x_8 is fast if and only if x_8 is excited we can infer that for all x_8, if x_8 were fast, then x_8 is excited via universal biconditional elimination. Finally, from the fact that for all x_8, if x_8 were fast, then x_8 is excited, and that for all x_8, x_8 is fast we can infer that for all x_8, x_8 is excited via universal modus ponens. Therefore, the answer is yes.