What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_4, if x_4 makes tea, then x_4 is cooking. There is at least one x_4 for which x_4 will take a plane or x_4 will make tea. For all x_4, x_4 will cook if and only if x_4 will take a plane.
For all x_4, if x_4 cooks, then x_4 is taking a plane. For all x_4, if x_4 takes a plane, then x_4 is cooking.