Consider the following premises. r_2 <-> R_8(d). forall x_8: R_8(x_8) or S_8(x_8). ~r_2. Can we infer S_8(d) from them? If possible, name the inference rules being used at each step.
 From forall x_8: R_8(x_8) or S_8(x_8) we can infer R_8(d) or S_8(d) via universal instantiation. From r_2 <-> R_8(d), ~r_2 we can infer ~R_8(d) via biconditional elimination. Finally, from R_8(d) or S_8(d), ~R_8(d) we can infer S_8(d) via disjunctive syllogism. Therefore, the answer is yes.