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, if x_8 works, then x_8 is not rich. For all x_8, if x_8 works, then x_8 is an astronaut. For all x_8, x_8 is rich and x_8 will read a book. For all x_8, if x_8 were an astronaut, then x_8 is working.
For all x_8, x_8 is rich can be inferred via the universal simplification rule. For all x_8, x_8 will read a book can be inferred via the universal simplification rule. For all x_8, x_8 will work if and only if x_8 is an astronaut can be inferred via the universal biconditional introduction rule. For all x_8, x_8 is an astronaut if and only if x_8 will work can be inferred via the universal biconditional introduction rule.