What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_7, if x_7 were a cashier, then x_7 is sad. For all x_7, if x_7 were sad, then x_7 is playing tennis. For all x_7, x_7 is a cashier and x_7 is happy.
For all x_7, if x_7 were a cashier, then x_7 is playing tennis. For all x_7, x_7 is a cashier. For all x_7, x_7 is happy.