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: For all x_7, x_7 will play a game if and only if x_7 will play squash. For all x_7, if x_7 plays squash, then x_7 is fast. For all x_7, x_7 will not read a book. For all x_7, x_7 will read a book if and only if x_7 is fast.
For all x_7, if x_7 plays a game, then x_7 is playing squash can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 reads a book, then x_7 is fast can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 plays squash, then x_7 is playing a game can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were fast, then x_7 is reading a book can be inferred via the universal biconditional elimination rule. For all x_7, x_7 is not fast can be inferred via the universal biconditional elimination rule.