What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_17, if x_17 plays tennis, then x_17 is playing squash. If William were a sailor, then Susan is playing tennis. Susan is playing squash if and only if William is a sailor.
If Susan plays squash, then William is a sailor. If William were a sailor, then Susan is playing squash.