Consider the following premises. Q_8(a_5) <-> q. forall x_8: P_8(x_8) <-> Q_8(x_8). forall x_8: ~P_8(x_8). Can we infer q from them? If possible, name the inference rules being used at each step.
 From forall x_8: P_8(x_8) <-> Q_8(x_8), forall x_8: ~P_8(x_8) we can infer forall x_8: ~Q_8(x_8) via universal biconditional elimination. From forall x_8: ~Q_8(x_8) we can infer ~Q_8(a_5) via universal instantiation. Finally, from Q_8(a_5) <-> q, ~Q_8(a_5) we can infer ~q via biconditional elimination, which contradicts q. Therefore, the answer is no.