What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_9, if x_9 were a mechanic, then x_9 is playing tennis. For all x_9, if x_9 reads a book, then x_9 is a mechanic. There is at least one x_9 for which x_9 will read a book if and only if x_9 will play tennis.
For all x_9, if x_9 reads a book, then x_9 is playing tennis. There is at least one x_9 for which if x_9 reads a book, then x_9 is playing tennis. There is at least one x_9 for which if x_9 plays tennis, then x_9 is reading a book.