Cho x, y thỏa mãn x + y = -1 và xy = -12. Tính:

a) A = x² + 2xy + y²

b) B = x² + y²

c) C = x³ + 3x²y + 3xy² + y³

d) D = x³ + y³

Chứng minh đẳng thức sau:

a) (a + b + c) . (a - b + c) = a² - b² + c² + 2ac

b) (3x + 2y) . (3x - 2y) - (4x - 2y) . (4x + 2y) = -7x²

c) (x - 1) . (x² + x + 1) - (x +1) . (x² - x +1) = -2

d) (2x + 1) . (4x² - 2x + 1) - (2x - 1) . (4x² +2x + 1) = 2

e) (x - 2y) . (x² + 2xy + 4y²) - (2x - 1) . (x² + 2xy + 4y²) = -16y³

I. Combine into one sentence with "too" or "either".

1. They can play tennis. We can play table tennis.

................................................................................................................

2. He sings love songs very well. His sister sings love songs very well.

................................................................................................................

3. I write diary every night. My mother writes diary every night.

................................................................................................................

4. My father doesn't drink beer. My mother doesn't drink beer.

...............................................................................................................

5. She is swimming in the pool. Her children are swimming in the pool.

...............................................................................................................

6. Hoa ate bread with milk for breakfast. Hoa's uncle ate bread with milk for breakfast.

...............................................................................................................

7. She didn't watch TV last night. Her husband didn't watch TV last night.

...............................................................................................................

8. They mustn't stay up late. Their friends mustn't stay up late.

...............................................................................................................

9. Milk is good for your health. Fruit juice is good for your health.

...............................................................................................................

10. Betty does morning exercise. Betty's aunt does morning exercise.

...............................................................................................................

II. Complete sentence with too or either.

1. We often go to the library on Sunday afternoon, they ..........................................................................

2. Susan can speak Japanese, Tom ...........................................................................................................

3. Minh didn't see the train, Nga ..............................................................................................................

4. Hoa will fly to Hong Kong next month, and her mother ......................................................................

5. THe pineapples aren't ripe. And the durians .........................................................................................

6. March is hot, and May ...........................................................................................................................

7. The boys shouldn't smoke cigarettes and the girls ................................................................................

8. I don't know how to use a computer and my friends .............................................................................

9. She likes eggs, and her brothers .............................................................................................................

10. They stayed at home last night, and their children ...............................................................................

III. Supply the correct passive form of the verbs in brackets.

1. This computer ....................... (use) for two years.

2. America ............................ (discover) by Christopher Columbus.

3. I think this institution .......................... (widen) twice since 1999.

4. Sydney Opera House in Australia ............................. (finish) in 1973.

5. My sister is studying law at Viet Nam National University. Ho Chi Minh city now. This university ......................... (situate) in Thu Hue District.

6. The Great Wall in China .................................. (build) many centuries ago.

7. David and his father ................................. (visit) the Temple of Literature last week.

8. The Golden Gate Bridge in San Francisco ............................ (complete) in 1937.

9. The University of Cambridge ........................... (from) in 1209. It is always considered to be one of the most prestigious universities in the world.

10. BurjKhalifa in Dubai, the highest building in the word, ............................ (open) in 2010.

Viết một đoạn văn nêu thái độ của em đối với gia đình.

Cho tam giác nhọn ABC. Qua A kẻ AH vuông góc BC (H thuộc BC). Từ H vẽ HK vuông góc với AC (K thuộc AC). Qua K vẽ đường thẳng song song BC cắt AB tại E.
a) Chứng minh AH vuông góc EK

b) Qua A vẽ AD vuông góc AB (D và C nằm khác phia đối với AB) đồng thời AD = AB. Vẽ AF vuông góc AC (F và B nằm khác phía đối với AC) và AF = AC. Chứng minh BF = DC và BE vuông góc DC.

I. Combine the sentences. Use the words in brackets.

1. Huyen Mi sings beautifully. Her sister sings more beautifully than her. (AS ... AS)

....................................................................................................................................................

2. The new sculpture is 4 metres high. The old sculpture is 4.2 metres high. (AS ... AS)

....................................................................................................................................................

3. Linh likes pop music. Her brother likes pop music. (TOO)

....................................................................................................................................................

4. Van Gogh is Dutch. Picasso is Spanish. (NATIONALITY ... DIFFERENT)

....................................................................................................................................................

5. This house is green. That house is green. (COLOR ... DIFFERENT)

....................................................................................................................................................

II. Rewrite the sentences, using the given words.

1. The last time she ate this kind of food was five years ago.

She .................................................................................................................................................

2. The last time she ate this kind of food was five years ago.

She .................................................................................................................................................

3. We can't afford to buy the car.

The car is .......................................................................................................................................

4. They began studying English in 2004.

They ............................................................................................................................................

5. People say that he beats his wife.

He is said to ...................................................................................................................................

6. She is more beautiful than her younger sister.

Her ..............................................................................................................................................

7. We spent five hours getting to London.

It took .........................................................................................................................................

8. Tim is better at English than Susan.

Susan isn't ..................................................................................................................................

9. You ought to go to school now.

It's time .......................................................................................................................................

10. Listening to music gives him pleasure.

He enjoys ....................................................................................................................................