Consider the following premises. For all x_7, if x_7 were an electrician, then x_7 is taking a plane. There is at least one x_7 for which x_7 will take a plane if and only if x_7 is excited. For all x_7, x_7 will drive a car or x_7 is excited. For all x_7, x_7 will not drive a car or x_7 is an electrician. Can we infer the following from them? If we can, name the inference rule being used: For all x_7, x_7 will not take a plane.
 From the fact that for all x_7, x_7 will drive a car or x_7 is excited, and that for all x_7, x_7 will not drive a car or x_7 is an electrician we can infer that for all x_7, x_7 is excited or x_7 is an electrician via universal resolution. From the fact that there is at least one x_7 for which x_7 will take a plane if and only if x_7 is excited we can infer that there is at least one x_7 for which if x_7 were excited, then x_7 is taking a plane via existential biconditional elimination. Finally, from the fact that there is at least one x_7 for which if x_7 were excited, then x_7 is taking a plane, that for all x_7, if x_7 were an electrician, then x_7 is taking a plane, and that for all x_7, x_7 is excited or x_7 is an electrician we can infer that there is at least one x_7 for which x_7 will take a plane via existential disjunction elimination, which contradicts that For all x_7, x_7 will not take a plane. Therefore, the answer is no.