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, x_4 will make tea if and only if x_4 will play squash. There is at least one x_4 for which x_4 is not a scientist. For all x_4, x_4 is a scientist if and only if x_4 will play squash.
For all x_4, if x_4 makes tea, then x_4 is playing squash. For all x_4, if x_4 were a scientist, then x_4 is playing squash. For all x_4, if x_4 plays squash, then x_4 is making tea. For all x_4, if x_4 plays squash, then x_4 is a scientist. There is at least one x_4 for which x_4 will not play squash.