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_9, if x_9 plays a game, then x_9 is reading a book. There is at least one x_9 for which x_9 will work if and only if x_9 will read a book. For all x_9, x_9 will play a game.
For all x_9, x_9 will read a book can be inferred via the universal modus ponens rule. There is at least one x_9 for which if x_9 works, then x_9 is reading a book can be inferred via the existential biconditional elimination rule. There is at least one x_9 for which if x_9 reads a book, then x_9 is working can be inferred via the existential biconditional elimination rule.