Method is the key, first of all, what does the topic require? Then analyze the relationship between the conditions of the topic and the requirements of the topic, and use a hypothetical number (x) to establish this relationship. If a number cannot be solved, boldly quote multiple unknowns. Finding out their relational expressions is the key to make the requirements effective.

Also, when solving a problem, we should consider whether the solution of the topic meets the actual requirements, and check the completed questions before writing them on the answer sheet, so that we will have more confidence and grasp when answering other questions.