`(2x+5)^2-(x-9)^2`
`=(2x+5-x+9)(2x+5+x-9)`
`=(x+14)(3x-4)`
Công thức: `A^2-B^2=(A-B)(A+B)`
Đáp án+Giải thích các bước giải:
`= (2x + 5 - x + 9) . (2x + 5 + x - 9)`
`= (2x - x + 5 + 9) . (2x + x + 5 - 9)`
`= (x + 14) . (3x - 4)`
`→` Ta áp dụng công thức: `A^2 - B^2 = ( A - B )( A + B )`
Xác định tốc độ góc của 1 điểm trên mặt đất.
Phân tích đa thức thành nhân tử Nhanh Nhanh với
Bài 1. Đọc đoạn văn :“Nàng rót chén rượu đầy…muôn dặm quan san” và thực hiện yêu cầu: Đoạn văn có sử dụng các câu văn biền ngẫu. Tác dụng của các câu văn biền ngẫu ấy ?
giúp mình với,mình cần lời giải chính xác thôi(sẵn cho mình xin lời giải thích luôn:))
16. He said, “My wife has just bought a diamond ring.” A. He said that his wife had just bought a diamond ring. B. He said that my wife had just bought a diamond ring. C. He said that his wife has just bought a diamond ring. D. he said that his wife just bought a diamond ring. 17. “I will come with you as soon as I am ready”, she said to Philip. A. She said to Philip he will come to see you as soon as he I am ready. B. She told Philip she will come to see her as soon as she was ready. C. She told Philip she would come to see you as soon as she was ready. D. She told Philip she would come to see him as soon as she was ready. 18. “I wrote to him yesterday” A. She said to me I wrote to him the day before. B. She told me she wrote to him yesterday. C. She told me she had written to him yesterday. D. She told me she had written to him the day before. 19. “He is talking to your sister”, She said to me. A. She told me he was talking to your sister. B. She told me she was talking to my sister. C. She told me he was talking to my sister. D. She told me he was talking to her sister. 20. Miss White said to him, “Why are you so late? Did your car have a flat fire?” A. Miss White told him why was he so late and did your car have a flat fire B. Miss White asked him why was he so late and did your car have a flat fire. C. Miss White asked him why was he so late and if your car have a flat fire. D. Miss White asked him why he was so late and whether his car had a flat fire. 21. . He said "If I had enough money, I could buy that dictionary." A. He said if he had enough money, he could buy that dictionary B. He said if he had had enough money, he could buy that dictionary. C. He said if he had enough money, he could have bought that dictionary. D. He said if he had had enough money, he could have bought that dictionary. 22. Tom: “ Why don’t you study hard for the coming exam, Ba” A. Tom advised me not to study hard for the coming exam B. Tom advised me to study hard for the coming exam C. Tom advised Ba not to study hard for the coming exam D. Tom advised Ba to study hard for the coming exam. 23. He asked me what……………………………………….. A. time was it B. time is it C. time it was D. none is correct. 24. She asked me……..the seat………..or not a. If / had occupied b. Whether / was occupied c. If / has been occupied d. Whether / occupied 25. The policeman asked us……….. a. had any of us seen the accident happen. b. If had any of us seen the accident happen c. Whether any of us had seen the accident happen d. that if any of us had seen the accident happen 26. I asked him………..,but he said nothing a. what the matter was b. what was the matter c. the matter was what d. what’s the matter was 27. James………..him up when the bus reached the square a. told me wake b. asked me to wake c. said me to wake d. requested me waking 28. I wonder………….we’ll catch the bus………we’ll take a taxi a. if / and whether b. whether / or that c. if / or that d. whether / or whether 29. Excuse me. Could you tell me………………? a. what time is it b. what is the time c. what time it is d. it is what time 30. We wonder……….from his office after that scandal a. why did he not resign b. why he did not resign c. why he not resign d. why didn’t he resign
tổng 3 người là 100 tuổi. số tuổi của ông bằng 3/5 tổng ba người tuổi của em bằng 1/4 tuổi tìm 3 người ?
tổng điện tích dương có trong 12g nguyên tử C
em cần phải đúng nha mn cần cực kỳ đúng ạ ! V/ Make questions for the underlined words 1. I get up at five o’clock every day. 2. Hoa’s house has two floors. 3. Phong lives in a small house in the country. 4. We want two bottles of water. 5. My sister wants some oranges. 6. They would like three apples. 7 Miss Trang feels tired
Trục căn thức $\dfrac{4a}{2√a - √b}$ (a>b>0)
Ghi đầy đủ ko tắt và ghi theo cách của lớp 8
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