Consider the following premises. There is at least one x_4 for which if x_4 were excited, then x_4 is bored. For all x_4, x_4 is excited if and only if x_4 is bored. Can we infer the following from them? If we can, name the inference rule being used: For all x_4, if is not true that x_4 is bored if and only if x_4 is excited.
That contradicts the premises. Therefore the answer is no.