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DL
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H9
2 giờ trước (21:21)

Sửa đề là z-x không phải x-z nhé!

Đặt: `a=x-y;b=y-z;c=z-x` 

Ta có: `abc=9` và cần tính `B=a^3+b^3+c^3`

`B-3abc=a^3+b^3+c^3-3abc`

`=(a+b)^3-3ab(a+b)+c^3-3abc`

`=(a+b+c)[(a+b)^2-(a+b)c+c^2]-3ab(a+b+c)`

`=(a+b+c)(a^2+2ab+b^2-ab-ac+c^2-3ab)`

`=(a+b+c)(a^2+b^2+c^2-ab-ac-bc)`

Mà: `a+b+c=x-y+y-z+z-x=0`

`=>B-3abc=0<=>B=3abc=3*9=27` 

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H24
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H24
6 giờ trước (17:06)

1 A

2 D

3 D 

4 C

5 C

6 A

7 C

8 D

9 C

10 A

11 A

12 B

13 D

14 A

15 C

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Ẩn danh
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CX
Hôm qua lúc 21:37

mình dùng từ năm 2021

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H24
Hôm qua lúc 21:43

You Are So Bad

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H24
Hôm qua lúc 22:20

t nè

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Ẩn danh
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CX
Hôm qua lúc 20:23

hai câu thơ này không chỉ khắc họa vẻ đẹp của một vùng đất trong mùa xuân mà còn gợi lên cảm xúc yêu thiên nhiên, sự hòa quyện giữa con người và cảnh vật.

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TD
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CX
Hôm qua lúc 20:19

Thận là bộ phận quan trọng của hệ bài tiết vì chúng có vai trò chính trong việc lọc máu, loại bỏ các chất thải và độc tố ra khỏi cơ thể qua nước tiểu. Thận cũng điều chỉnh cân bằng nước, điện giải và acid-base, giúp duy trì môi trường nội môi ổn định. Ngoài ra, thận còn sản xuất các hormone quan trọng, như erythropoietin, điều chỉnh huyết áp và tham gia vào quá trình trao đổi chất.

học tốt 

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Ẩn danh
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H24
Hôm kia lúc 8:43

 x² + y² = (x + y)² - 2xy
25 = 5² - 2xy hay 25 = 25 - 2xy
0 = -2xy => xy = 0

ta có: x³ + y³ = (x + y) * (x² + xy + y²)
⇔ 5 * (25 + 0) = 5 x 25 = 125

vậy x³ + y³ = 125

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H24
Hôm kia lúc 8:18
1. If you had not been late, we would not have missed the bus 2. If she had studied, she would have passed the exam 3. If we had arrived earlier, we would have seen John 4. If they had gone to bed early, they would not have woken up late 5. If he had become a musician, he would have recorded a CD 6. If she had gone to art school, she would have become a painter 7. If I had been born in a different country, I would have learned to speak a different language 8. If she had gone to university, she would have studied French 9. If we had not gone to the party, we would not have met them 10. If he had taken the job, he would not have gone travelling 11. He would have been happier if he had stayed at home 12. She would have passed the exam if she had studied harder 13. We would not have got married if we had not gone to the same university 14. They would have been late if they had not taken a taxi 15. She would not have met him if she had not come to London 16. He would have taken a taxi if he had had enough money 17. I would have called you if I had not forgotten my phone 18. We would have come if we had been invited 19. She would not have done it if she had known you were ill 20. He would have been on time if he had left earlier
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H24
Hôm kia lúc 8:18
1. If you had not been late, we would not have missed the bus 2. If she had studied, she would have passed the exam 3. If we had arrived earlier, we would have seen John 4. If they had gone to bed early, they would not have woken up late 5. If he had become a musician, he would have recorded a CD 6. If she had gone to art school, she would have become a painter 7. If I had been born in a different country, I would have learned to speak a different language 8. If she had gone to university, she would have studied French 9. If we had not gone to the party, we would not have met them 10. If he had taken the job, he would not have gone travelling 11. He would have been happier if he had stayed at home 12. She would have passed the exam if she had studied harder 13. We would not have got married if we had not gone to the same university 14. They would have been late if they had not taken a taxi 15. She would not have met him if she had not come to London 16. He would have taken a taxi if he had had enough money 17. I would have called you if I had not forgotten my phone 18. We would have come if we had been invited 19. She would not have done it if she had known you were ill 20. He would have been on time if he had left earlier
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SN
18 giờ trước (4:38)

34 would never be - bought

35 would lose - ate

1 hadn't been - wouldn't have missed

2 had studied - would have passed

3 had arrived - would have seen

4 had gone - wouldn't have waken

5 had become - would have recorded

6 had gone - would have become

7 had been - would have learned

8 had gone - would have studied

9 hadn't gone - wouldn't have met

10 had taken - wouldn't have gone

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H24
Hôm kia lúc 8:17
1. If you had not been late, we would not have missed the bus2. If she had studied, she would have passed the exam3. If we had arrived earlier, we would have seen John4. If they had gone to bed early, they would not have woken up late5. If he had become a musician, he would have recorded a CD6. If she had gone to art school, she would have become a painter7. If I had been born in a different country, I would have learned to speak a different language8. If she had gone to university, she would have studied French9. If we had not gone to the party, we would not have met them10. If he had taken the job, he would not have gone travelling11. He would have been happier if he had stayed at home12. She would have passed the exam if she had studied harder13. We would not have got married if we had not gone to the same university14. They would have been late if they had not taken a taxi15. She would not have met him if she had not come to London16. He would have taken a taxi if he had had enough money17. I would have called you if I had not forgotten my phone18. We would have come if we had been invited19. She would not have done it if she had known you were ill20. He would have been on time if he had left earlier
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SN
18 giờ trước (4:39)

34 would never be - bought

35 would lose - ate

1 hadn't been - wouldn't have missed

2 had studied - would have passed

3 had arrived - would have seen

4 had gone - wouldn't have waken

5 had become - would have recorded

6 had gone - would have become

7 had been - would have learned

8 had gone - would have studied

9 hadn't gone - wouldn't have met

10 had taken - wouldn't have gone

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SN
18 giờ trước (4:39)

11 would have been - had stayed

12 would have passed - had studied

13 wouldn't have got - hadn't gone

14 wouldn't have been - hadn't taken

15 wouldn't have met - had come

16 would have taken - had had

17 would have called - hadn't forgot

18 would have come - had been

19 wouldn't have done - had known

20 would have been - had left

Bài 3

21 B

23 A

26 A

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H24
Hôm kia lúc 21:33

Bạn không đăng lại câu hỏi nhé.

->https://hoc24.vn/cau-hoi/.9378892995436

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SN
18 giờ trước (5:08)

1 If there air weren't polluted, people wouldn't live shorter

2 If Covid weren't spreading, Tom would study harder

3 If Tom studied hard, he would pass the exam

4 If he didn't do morning exercise, his health wouldn't be good

5 If Jane weren't sick, he could hang out

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SN
18 giờ trước (5:08)

6 If Linda felt well, she could go to school

7 If this car weren't expensive, he could buy it

8 If he didn't get the first prize, his mom wouldn't be happy

9 If I had much money, I would live in a small house

10 If my father didn't smoke, he wouldn't cough

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