What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Charles is playing tennis if and only if Patricia is happy. Charles is playing tennis if and only if James is a server. For all x_7, x_7 is happy if and only if x_7 is a taxi driver. James is not a server.
If Charles plays tennis, then Patricia is happy. If Charles plays tennis, then James is a server. If Patricia were happy, then Charles is playing tennis. If James were a server, then Charles is playing tennis. Charles is not playing tennis. For all x_7, if x_7 were happy, then x_7 is a taxi driver. For all x_7, if x_7 were a taxi driver, then x_7 is happy.