What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: If Linda plays tennis, then Richard is a server. Linda is playing tennis if and only if Linda is a mechanic. If Richard were a server, then Linda is playing tennis.
Linda is playing tennis if and only if Richard is a server can be inferred via the biconditional introduction rule. Richard is a server if and only if Linda is playing tennis can be inferred via the biconditional introduction rule. If Linda plays tennis, then Linda is a mechanic can be inferred via the biconditional elimination rule. If Linda were a mechanic, then Linda is playing tennis can be inferred via the biconditional elimination rule.