I found the original question for you, exactly the same /math/ 1 1568/ You can come to this website to search for ideas when you encounter math and physics problems in junior high school in the future. The question bank is huge, and there are similar questions without original questions. The interface is scientific. Can you also come for answers? Ask the group "Junior Middle School Learning Group 2 for the answer", and there are many mathematicians who can help you in the future. Hope to adopt.