What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_7, x_7 is not a writer. For all x_7, x_7 is a writer if and only if x_7 is rich. For all x_7, if x_7 were a musician, then x_7 is a police officer. For all x_7, x_7 is rich or x_7 is a musician.
For all x_7, if x_7 were a writer, then x_7 is rich. For all x_7, if x_7 were rich, then x_7 is a writer. For all x_7, x_7 is not rich.