Consider the following premises. w <-> p. ~p_8. p_8 <-> w. Can we infer ~p from them? If possible, name the inference rules being used at each step.
 From p_8 <-> w, ~p_8 we can infer ~w via biconditional elimination. From w <-> p we can infer p -> w via biconditional elimination. Finally, from p -> w, ~w we can infer ~p via modus tollens. Therefore, the answer is yes.