Well, we do it in different ways, and I don't have any teaching materials, so I can't help! I can't help you Few people can help you! I think you'd better withdraw the question! Maybe when someone writes the answer. These problems have also been exposed by the teacher! It doesn't matter if you don't short, as long as you actively find a teacher to understand the problem the next day! The teacher will not blame you, but will think that you are a good student who loves to learn!

Hope to adopt, thank you!