What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_6, if x_6 writes a letter, then x_6 is a cashier. For all x_6, x_6 will listen to a song or x_6 will play squash. For all x_6, x_6 will not play squash. For all x_6, x_6 will not listen to a song or x_6 will write a letter.
For all x_6, x_6 will play squash or x_6 will write a letter.