Consider the following premises. ~p_1. p_8 <-> p. p -> p_1. Can we infer p_8 from them?
 From p_8 <-> p we can infer p_8 -> p. From p -> p_1, ~p_1 we can infer ~p. Finally, from p_8 -> p, ~p we can infer ~p_8, which contradicts p_8. Therefore, the answer is no.