问题
计算题
因式分解：﹣4（x﹣2y）2+9（x+y）2．
答案
解：﹣4（x﹣2y）2+9（x+y）2
=[3（x+y）]2﹣[2（x﹣2y）]2
=（3x+3y+2x﹣4y）（3x+3y﹣2x+4y）
=（5x﹣y）（x+7y）
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因式分解：﹣4（x﹣2y）2+9（x+y）2．
解：﹣4（x﹣2y）2+9（x+y）2
=[3（x+y）]2﹣[2（x﹣2y）]2
=（3x+3y+2x﹣4y）（3x+3y﹣2x+4y）
=（5x﹣y）（x+7y）
| 完形填空。 | ||||
| Last year Tom left school. He came to Hong Kong to find a 1 . He went to one company after 2 company. But no one wanted him. Now he had 3 money. He had to go back to his small town. So he came to the station. He felt very sad and 4 . It was very late at night and the station was 5 of people. They were waiting to buy tickets of the last train. He bought the 6 ticket. And he was very happy. At that time, a woman with a crying baby walked to him. She asked him to 7 her the ticket. He gave her the ticket. He thought they needed it 8 than he did. After the train left, he sat on the bench and didn't know 9 to go. Just then an old man came and said, "Young man, I saw what you did to help the woman. I have a big company. I need a good young man like you. Would you like to 10 for me?" | ||||
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