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_7, x_7 is a bartender and x_7 is a cashier. For all x_7, x_7 is a bartender if and only if x_7 will cook.
For all x_7, x_7 is a bartender can be inferred via the universal simplification rule. For all x_7, x_7 is a cashier can be inferred via the universal simplification rule. For all x_7, if x_7 were a bartender, then x_7 is cooking can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 cooks, then x_7 is a bartender can be inferred via the universal biconditional elimination rule.