Consider the following premises. forall x_7: Q_7(x_7). exists x_7: Q_2(x_7) <-> S(x_7). forall x_7: S(x_7) -> ~Q_7(x_7). Can we infer exists x_7: Q_2(x_7) <-> S(x_7) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.