Tìm m để phương trình \(x^2-4\left(m+1\right)x+6m-5=0\) có 2 nghiệm phân biệt x₁, x₂ làm cho biểu thức A = \(\frac{1}{x^2_1+x_2^2-3x_1x_2}\) đạt giá trị lớn nhất.

ΔABC vuông tại A(2;2). Biết C(4;-2) và B thuộc Oy, tìm tọa độ B và H là hình chiếu của A lên BC.

1) The man that we are talking about is a famous scientist.

➝ The man about ...

2) The tree that we picked these fruits from is in front of the house.

➝ The tree from ...

3) The city that we were born in is very large.

➝ The city in ...

4) Do you remember the day? We first met on that day.

➝ Do you remember the day on ...

5) The manager has just announced his retirement. We have all depended on him so much.

➝ The manager on ...

Fill in the blanks with Relative pronoun or Relative adverbs. Put commas when they are needed:

1) Alexander Fleming ... discovered penicillin received the Nobel Prize in 1945.

2) The book ... I need can't be found in the library.

3) Here is the beach ... is the safest for swimmers.

4) Do you know the American woman ... name is Margaret Mitchell.

5) Jim ... I have known for ten years is one of my closest friends.

6) John found a cat ... leg was broken.

7) Don't sit on the chair ... the leg is broken.

8) This tree ... branches are dry should be cut down.

9) The child smiled at the woman ... he didn't know.

10) That woman ... name I don't remember is a doctor.

11) Children enjoy reading the books ... have coloured pictures.

12) I met someone ... said he knew you.

13) The noise ... he made woke everybody up.

14) The film is about a spy ... wife betrays him.

15) Those girls ... serve in the restaurant are the owner's daughters.

16) The house ... walls and roof are made of glass is a green house.

17) Rod Lee ... sister I know is a film actor.

18) Mr. Bake will buy the house ... is opposite to my house.

19) You have to take care of the books ... you borrowed from the library.

20) Karl Marx ... theories have changed the world's history is the German Philosopher.

21) Let me see all the letters ... you have written.

22) Is there anyone ... can help me do this?

23) Mr. Brown ... is only 34 is the director of this company.

24) The chief of Police, ... work is very important, takes care of the public safety.

25) I know a place ... roses grow in abundance.

26) The teacher with ... we studied last year no longer teaches in our school.

27) They showed me the hospital ... buildings had been destroyed by bombings.

28) We saw many soldiers and tanks ... were moving to the front.

29) We must find a time ... we can meet and a place ... we can talk.

30) The decision was postponed, ... was exactly what he wanted.

Relative clause:

1) Astronomy is one of the world oldest sciences. It is the study of planets and stars.

➞

2) The vegetables are grown without chemicals. They are sold in supermarkets.

➞

3) People have marched to London. They are protesting against pollution.

➞

4) The police never found the money. It was stolen in the robbery.

➞

5) There was a big red car. It had been parked outside the house.

➞

6) Libya is a leading producer of oil. It is a country in North Africa.

➞

7) A chemical company has been bankrupt. It employed 4000 people.

➞

8) A new drug may gives us eternal youth. It was developed by a British university.

➞

9) A new motorway is planned. It will cost 500 million pound.

➞

10) Some weapons belong to the IRA. They are found at a flat in Bristol.

➞

11) John Quincy Adams was born on July 11, 1767. He was the sixth president of the United States.

➞

12) There were some children. They were swimming in the river.

➞

13) Tennis fans have been queuing all night at Wimbledon. They hope to buy tickets.

➞

14) Some paintings haven't been found yet. They were stolen from the museum.

➞

15) Two languages, Finnish and Swedish, are used in Helsinki. It is the capital of Finland.

➞

Một ô tô khối lượng 1 tấn, bắt đầu khởi hành chuyển động trên mặt đường ngang có hệ số ma sát lăn và ma sát trượt lần lượt là μ_l = 0,05 và μ_t = 0,5. Biết lực kéo động cơ có độ lớn 1000 N.

a) Tìm quãng đường đi được và vận tốc xe đạt được sau 20 s chuyển động.

b) Sau thời gian trên thì xe tắt máy. Tìm quãng đường đi được và thời gian chuyển động của xe sau khi tắt máy, trong 2 trường hợp sau:

- Trường hợp 1: Sau khi tắt máy, xe không hãm thắng.

- Trường hợp 2: Sau khi tắt máy, xe hãm thắng. Coi như ngay sau khi hãm thắng bánh xe lập tức ngừng quay và trượt trên mặt đường.