Consider the following premises. For all x_11, x_11 is a poet. For all x_11, if x_11 were happy, then x_11 is excited. For all x_11, x_11 will play tennis or x_11 is happy. For all x_11, x_11 is excited if and only if x_11 will play tennis. Can we infer the following from them? If we can, name the inference rule being used: Sarah is a poet.
 From the fact that for all x_11, x_11 is excited if and only if x_11 will play tennis we can infer that for all x_11, if x_11 plays tennis, then x_11 is excited via universal biconditional elimination. From the fact that for all x_11, if x_11 plays tennis, then x_11 is excited, that for all x_11, if x_11 were happy, then x_11 is excited, and that for all x_11, x_11 will play tennis or x_11 is happy we can infer that for all x_11, x_11 is excited via universal disjunction elimination. From the fact that for all x_11, x_11 is excited, and that for all x_11, x_11 is a poet we can infer that for all x_11, x_11 is excited and x_11 is a poet via universal conjunction. From the fact that for all x_11, x_11 is excited and x_11 is a poet we can infer that Sarah is excited and Sarah is a poet via universal instantiation. Finally, from the fact that Sarah is excited and Sarah is a poet we can infer that Sarah is a poet via simplification. Therefore, the answer is yes.