Consider the following premises. r -> r_3. r_8 -> r. ~u. r_3 -> r_8. u <-> r. Can we infer r_8 from them?
 From r -> r_3, r_3 -> r_8 we can infer r -> r_8. From u <-> r, ~u we can infer ~r. From r -> r_8, r_8 -> r we can infer r <-> r_8. Finally, from r <-> r_8, ~r we can infer ~r_8, which contradicts r_8. Therefore, the answer is no.