Consider the following premises. q. S(a_14) <-> q_7. forall y: ~S(y). Can we infer ~q_7 and q from them? If possible, name the inference rules being used at each step.
 From forall y: ~S(y) we can infer ~S(a_14) via universal instantiation. From S(a_14) <-> q_7, ~S(a_14) we can infer ~q_7 via biconditional elimination. Finally, from ~q_7, q we can infer ~q_7 and q via conjunction. Therefore, the answer is yes.