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: There is at least one x_7 for which if x_7 cooks, then x_7 is excited. For all x_7, if x_7 sleeps, then x_7 is a musician. For all x_7, x_7 is a musician if and only if x_7 is excited. For all x_7, x_7 will sleep or x_7 will cook.
For all x_7, if x_7 were a musician, then x_7 is excited can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were excited, then x_7 is a musician can be inferred via the universal biconditional elimination rule.