Chuyển câu chủ động thành câu bị động 1. Someone cleans the floor every morning. 2. They cancelled all the flights because of the fog. 3. People don’t use this road very often. 4. Somebody is using the computer at the moment. 5. People should send their complaints to the main office. 6. The police have just released John. 7. A short circuit could have caused the fire. 8. Somebody has robbed the bank near our house. 9. The old man treated the little boys badly. 10. My brother bought that book yesterday. 11. The boys carried the heavy box into the room last week. 12. Our parents warned us not to go out alone. 13. They are building a new highway around the city next year. 14. They had to postpone the meeting because of illness. 15. We will send you the results as soon as they are ready. 16. His colleagues gave him a present when he retired. 17. They installed a new pump to supply water for the town. 18. The secretary told me to wait outside. 19. The computer is used to solve the complex problems. 20. They didn’t offer Ann the job. 21. They have sold that old house at the end of the road. 22. They had cancelled the soccer match. 23. No one has collected the rubbish this week. 24. You should peel and chop the onion and then fry it. 25. You must turn off all the switches before leaving the room. 26. They are going to clear those slums. 27. They are going to mend the roof tomorrow morning. 28. The farmer is going to enlarge the farm. 29. She is going to buy a cookery book next month. 30. Someone is going to serve Jack breakfast in bed on his birthda

2 kg nước được đun nóng từ 20độk C đến khi sôi và 0,5 kg đã biến thành hơi .Tính nhiệt lượng cần thiết để làm việc đó.Nhiệt lượng cần thiết làm việc đó.Nhiệt dung rieng của nước là 4200J/kg.K,nhiệt hóa hơi của nước là 2,3.10^6J/kg

Tính giá trị của biểu thức:

a)\(2\dfrac{1}{547}\).\(\dfrac{3}{211}\)-\(\dfrac{546}{547}\).\(\dfrac{1}{211}\)-\(\dfrac{4}{547.211}\)

b)x¹⁵-8x¹⁴+8x¹³-8x¹²+...-8x²+8x-5 với x=7

c)\(2\dfrac{1}{315}\).\(\dfrac{1}{651}\)-\(\dfrac{1}{105}\).\(3\dfrac{650}{651}\)-\(\dfrac{4}{315.651}\)+\(\dfrac{4}{105}\)

a)Tim so nguyen x va y biet :

5/x+y/4=1/8

b)Tim so nguyen x de A co gia tri la 1 so nguyen biet :

A=(căn x +1) /(căn x -3) (x lớn hơn hoặc bằng 0)

chứng minh rằng từ hệ thức a+b/a-b=c+d/c-d ta có hệ thức a/b=c/d

1)chứng tỏ rằng:A = 75.(4²⁰⁰⁴+4²⁰⁰³+...+4²+4+1)+25 chia het cho 100

2)độ dài ba cạnh của tam giác tỉ lệ với 2;3;4.Ba chieu cao tuong ung voi ba canh do ti le voi ba so nao?

a) cho a/b=b/c=c/a và a+b+c khác 0; a=2005,Tính b,c.

b) Tính

9/10-1/90-1/72-1/56-1/42-1/30-1/20-1/12-1/6-1/2

a)chứng minh rằng nếu a+c=2b và 2bd=c b+d) thì a/b=c/d với b,d khác 0

b) tìm moi so nguyen thoa man : x² - 2y² = 1

a) Tim so nguyen a de a² + a + 3 / a+1 la so nguyen.o cho x-2xy+y=0

b)Tim so nguyen x,y sao cho x-2xy+y=0.