What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Sarah were fast, then Sarah is taking a plane. For all x_9, x_9 is fast if and only if x_9 will take a plane.
For all x_9, if x_9 were fast, then x_9 is taking a plane. For all x_9, if x_9 takes a plane, then x_9 is fast.