Consider the following premises. p_3 or q_7. p_3 -> q_1. q_1 -> t. t or ~q_7. Can we infer ~t from them?
 From t or ~q_7 we can infer q_7 -> t. From p_3 -> q_1, q_1 -> t we can infer p_3 -> t. Finally, from p_3 -> t, q_7 -> t, p_3 or q_7 we can infer t, which contradicts ~t. Therefore, the answer is no.