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_8, x_8 will make tea if and only if x_8 is a cashier. For all x_8, x_8 is not a cashier. For all x_8, x_8 will make tea if and only if x_8 is a mechanic.
For all x_8, if x_8 makes tea, then x_8 is a cashier can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 makes tea, then x_8 is a mechanic can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a cashier, then x_8 is making tea can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a mechanic, then x_8 is making tea can be inferred via the universal biconditional elimination rule. For all x_8, x_8 will not make tea can be inferred via the universal biconditional elimination rule.