Consider the following premises. For all x_7, x_7 is a scientist if and only if x_7 will take a plane. For all x_7, if x_7 were a scientist, then x_7 is poor. For all x_7, x_7 is a police officer if and only if x_7 is poor. For all x_7, x_7 is not a police officer. Can we infer the following from them? If we can, name the inference rule being used: For all x_7, x_7 is not a police officer.
That is one of the premises. Therefore, the answer is yes.