Consider the following premises. u. q_17 -> w_1. u -> t. s or q_17. s -> w_1. Can we infer t from them? If possible, name the inference rules being used at each step.
 From s -> w_1, q_17 -> w_1, s or q_17 we can infer w_1 via disjunction elimination. Finally, from u -> t, u we can infer t via modus ponens. Therefore, the answer is yes.