Giả Sử D là 1 điểm nằm trong tam giác nhọn ABC sao cho ADB=ACB+90 và AC.BD=AD.BC> Cmr AB.CD/AC.BD=$\sqrt{2}$

ai giải đc câu này tớkết bạn liền. 

có bn ô đây

Help với:
Rewrite the sentences. Use present or past participle clauses.
7. She came in and she looked furious.
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8. He set off on his journey and he carried only one small bag.
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9. I’ve changed my job since I last wrote to you.
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10. Before I give you an answer, I need to discuss the situation with my parents.
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11. He left school and then he worked in a restaurant for a year. (Begin: Having...)
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12. She switched on her computer and started to work.
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13. We turned the corner and we saw a huge traffic jam ahead of us.
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14. After he bought the painting, he discovered that it was a fake. (Begin: Having...)
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15. I was exhausted by lack of sleep and dozed off at my desk.
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16. Since I was promoted, I’ve had no time to go out.
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17. After Richard was released from prison, he couldn’t find a job anywhere.
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18. When she was caught, she confessed to the crime.
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19. If I am allowed to do so, I would like to present my side of the argument.
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20. Unless he is treated with more respect, he will leave the company.
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21. Although it was written many years ago, the book is still relevant today.
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