What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, x_12 will work if and only if x_12 is a writer. For all x_12, x_12 is a writer and x_12 is poor. There is at least one x_12 for which x_12 will play tennis.
For all x_12, x_12 is a writer. For all x_12, x_12 is poor. For all x_12, if x_12 works, then x_12 is a writer. For all x_12, if x_12 were a writer, then x_12 is working.