What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_9 for which x_9 will take a plane. For all x_9, x_9 will not work. For all x_9, x_9 will work or x_9 will not take a plane.
Since the premises are contradictory, we can infer anything from them.