Tìm n thuộc N để có phép chia hết:

a) xⁿ⁺². yⁿ⁺¹ : x⁵. y⁶

b) (x + y)⁶ⁿ. (x - y)⁵ : (x + y)¹⁸. (x - y)ⁿ

c) (12x³y⁷ + 9x⁴y⁵ - 3x⁵y⁸) : 3xⁿ⁺¹. yⁿ⁺³

d) (5x^n-2. y⁷ - 8xⁿ⁺². y⁸) : 5x³. yⁿ⁺¹

CMR không có các số x, y nào thỏa mãn các đẳng thức sau:

a) 3x² + y² + 10x - 2xy + 26 = 0

b) 4x² + y² + 4x + 2y + 6 = 0

c) 4x² + 3y² - 4x + 30y + 78 = 0

d) 3x² + 6y² - 12x - 20y + 40 = 0

1. Thu gọn:

a) 5x. (x-3) - x. (5x+1)

b) -3x. (x-1) - x. (x+1) + 4x. (x-2)

c) (3x-1). (x-2) + (x-1). (x+1)

d) (4x-3). (2x-5) - (8x-2). (x-1)

2. Tìm x:

a) 3x. (x-3) - x. (3x-2) = 2

b) -2x. (x+1) - 3. (1-x) + 2x²

c) (x-2). (x+2) + (3.x). (x+1) = 0

d) (2x-1). (x+3)- (x-2). (2x+1) = 10

I. Turn these sentences into passive voice.

1. He ofen does exercises every night.

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

2. She usually decorates the room at weekends.

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

3. Daisy always sings country songs.

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

4. She ofen gives her sister sweets.

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

5. Nam and Peter ofen water these trees.

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

6. They produce cars in this country.

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

7. We don't allow smoking in this restaurant.

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

8. Do pupils clean the room every day?

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

II. Complete the second sentence in each pair so htat it has similar meaning to the first sentence.

1. People invented the wheel thousands of years ago,

The wheel ............................................................................

2. My father waters these flower every morning.

These flowers ......................................................................

3. People use computers all over the world.

Computers ...........................................................................

4. Are they building a statue of Chu Van An?

Is ..........................................................................................?

5. John invited Fiona to his birthday party last night.

Fiona .....................................................................................

6. They keep many ancient things in museums.

Many ancient things .............................................................

7. Do four busy streets surround the Temple of Literature?

Is ...........................................................................................?

8. People make many famous films in Hollywood.

Many famous films ...............................................................

9. Her mother is preparing the dinner in the kitchen.

The dinner ..............................................................................

10. I do all my homework on my computer.

All my homework ..................................................................