What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x, x will take a plane. For all x_10, x_10 will play tennis if and only if x_10 will take a plane.
For all x_10, if x_10 plays tennis, then x_10 is taking a plane can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 takes a plane, then x_10 is playing tennis can be inferred via the universal biconditional elimination rule.