Consider the following premises. t_2. ~q_2. s_2 -> q_2. t_2 -> q_10. Can we infer s_2 from them? If possible, name the inference rules being used at each step.
 From t_2 -> q_10, t_2 we can infer q_10 via modus ponens. Finally, from s_2 -> q_2, ~q_2 we can infer ~s_2 via modus tollens, which contradicts s_2. Therefore, the answer is no.