Tìm x,y,z biết:

\(x^2+y^2+z^2=4x-2y+6z-14\)

Hướng dẫn:Đưa về dạng \(A^2\left(x\right)+B^2\left(y\right)+C^2\left(z\right)=40\)

13.It is reported that two people were seriously injured in the accident.

Two people_____________________________________

14.It is said that three men were arrested after the explosion.

Three man_________________________________________________

15.They are the best players in this game.

No player____________________________

16.They think that the old man died on the way to the hospital.

It_______________________________

The old man__________________________

11.They don't have much time.They can't have lunch with us.(enough)

_________________________________________________

12.She practise speaking English everyday.She wants to speak it fluently.(in order to)

_______________________________________________________

Rewrite the sentences without changing their meanings.

9.Because Mr Tam was seriously ill last night,he didn't join our party.

Because of___________________________________

10.Despite the rainy wheather tonight,we dicided to go out together.

Although________________________________________

Rewrite the sentences without changing their meanings.

4.Be careful or you'll fall of your bike.

____________________________________________________

5.Our teacher is always a careful driver.(drives)

__________________________________________

6.Mr Tam went to work by car some years ago,but now he cycles.(used)

_________________________________________

7.Road users should obey traffic rules strictly.(obeyed)

___________________________________________________

8.My mother washed clothes by hand in the past,but she no longer does it now.(used)

_________________________________________________________

Rewrite the sentences without changing their meanings.

3.He has a number of relatives living nearly,but he never visits them(even though)

______________________________________________________

Rewrite the sentences without changing their meanings.

2.They said:"We can't talk to her if she doesen't apologise to us for her bad behaviour."

___________________________________________________

Rewrite the sentences without changing their meanings.

1.Who cleaned this car this afternoon?(cleaned)

_________________________________________________

Một chiếc tàu bị thủng một lỗ ở độ sâu 2,8m. Người ta đặt một miếng vá áp vào lỗ thủng từ phía trong. Hỏi cần một lực tối thiểu bằng bao nhiêu để giữ miếng vá nếu lỗ thủng rộng 150 cm² và trọng lượng riêng của nước là 10000N/m³

Một ống thủy tinh được bịt kín một đầu bằng một màng cao su mỏng. Nhúng ống thủy tinh vào một chậu nước (H.8.8). Màng cao su có hình dạng như thế nào trong các trường hợp sau đây ?

a) Khi chưa đổ nước vào ống thủy tinh.

b) Khi đổ nước vào ống sao cho mực nước trong ống bằng mực nước ngoài ống.

c) Khi đổ nước vào ống sao cho mực nước trong ống thấp hơn mực nước ngoài ống.

d) Khi đổ nước vào ống sao cho mực nước trong ống cao hơn mực nước ngoài ống