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_8, if x_8 plays tennis, then x_8 is cooking. For all x_8, x_8 will cook if and only if x_8 will play tennis. There is at least one x_8 for which if x_8 plays tennis, then x_8 is cooking.
For all x_8, if x_8 cooks, then x_8 is playing tennis can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 plays tennis, then x_8 is cooking can be inferred via the universal biconditional elimination rule.