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 were happy, then x_9 is working. For all x_9, if x_9 goes running, then x_9 is happy. For all x_9, if x_9 were happy, then x_9 is making tea. For all x_9, if x_9 works, then x_9 is happy. For all x_9, x_9 will work or x_9 will go running.
For all x_9, if x_9 goes running, then x_9 is working can be inferred via the universal transitivity rule. For all x_9, if x_9 goes running, then x_9 is making tea can be inferred via the universal transitivity rule. For all x_9, if x_9 works, then x_9 is making tea can be inferred via the universal transitivity rule. For all x_9, x_9 is happy can be inferred via the universal disjunction elimination rule. For all x_9, x_9 is happy if and only if x_9 will work can be inferred via the universal biconditional introduction rule. For all x_9, x_9 will work if and only if x_9 is happy can be inferred via the universal biconditional introduction rule.