Consider the following premises. If Joseph were a soldier, then Jessica is taking a plane. For all x_14, x_14 is excited if and only if x_14 will take a plane. For all x_7, x_7 is a soldier if and only if x_7 is a server. Jessica is not excited. Can we infer the following from them? If we can, name the inference rule being used: Joseph is not a server.
 From the fact that for all x_14, x_14 is excited if and only if x_14 will take a plane we can infer that Jessica is excited if and only if Jessica is taking a plane via universal instantiation. From the fact that Jessica is excited if and only if Jessica is taking a plane, and that Jessica is not excited we can infer that Jessica is not taking a plane via biconditional elimination. From the fact that for all x_7, x_7 is a soldier if and only if x_7 is a server we can infer that Joseph is a soldier if and only if Joseph is a server via universal instantiation. From the fact that if Joseph were a soldier, then Jessica is taking a plane, and that Jessica is not taking a plane we can infer that Joseph is not a soldier via modus tollens. Finally, from the fact that Joseph is a soldier if and only if Joseph is a server, and that Joseph is not a soldier we can infer that Joseph is not a server via biconditional elimination. Therefore, the answer is yes.