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_10, if x_10 plays squash, then x_10 is cooking. For all x_10, x_10 will play squash if and only if x_10 will cook. For all x_10, if x_10 cooks, then x_10 is playing squash.
For all x_10, x_10 will play squash if and only if x_10 will cook can be inferred via the universal biconditional introduction rule. For all x_10, x_10 will cook if and only if x_10 will play squash can be inferred via the universal biconditional introduction rule. For all x_10, if x_10 plays squash, then x_10 is cooking can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 cooks, then x_10 is playing squash can be inferred via the universal biconditional elimination rule.