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_5, if x_5 plays a game, then x_5 is working. For all x_5, if x_5 works, then x_5 is playing a game. For all x_5, if x_5 works, then x_5 is not poor. For all x_5, x_5 is poor.
For all x_5, x_5 will not work can be inferred via the universal modus tollens rule. For all x_5, x_5 will play a game if and only if x_5 will work can be inferred via the universal biconditional introduction rule. For all x_5, x_5 will work if and only if x_5 will play a game can be inferred via the universal biconditional introduction rule.