Consider the following premises. ~q_2. t. q_2 or ~q_13. Can we infer ~q_13 from them? If possible, name the inference rules being used at each step.
 From q_2 or ~q_13 we can infer q_13 -> q_2 via rewriting. Finally, from q_13 -> q_2, ~q_2 we can infer ~q_13 via modus tollens. Therefore, the answer is yes.