Consider the following premises. forall x_9: P_9(x_9). P_9(a_8) <-> q_4. ~q_4. Can we infer Q_9(a_8) from them?
 From forall x_9: P_9(x_9) we can infer forall x_9: P_9(x_9) or Q_9(x_9). From forall x_9: P_9(x_9) or Q_9(x_9) we can infer P_9(a_8) or Q_9(a_8). From P_9(a_8) <-> q_4, ~q_4 we can infer ~P_9(a_8). Finally, from P_9(a_8) or Q_9(a_8), ~P_9(a_8) we can infer Q_9(a_8). Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.