Consider the following premises. p_8 <-> q. p_3 <-> p_8. Can we infer p_3 -> q from them?
 From p_8 <-> q we can infer p_8 -> q. From p_3 <-> p_8 we can infer p_3 -> p_8. Finally, from p_3 -> p_8, p_8 -> q we can infer p_3 -> q. Therefore, the answer is yes.