What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_9 for which x_9 is not rich. For all x_9, x_9 will read a book. For all x_9, x_9 will read a book if and only if x_9 is rich.
Since the premises are contradictory, we can infer anything from them.