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29 tháng 10 2023

`A= x^2+2xy-3x^2 +2y^2+3x^2-y^2`

`= (x^2-3x^2 +3x^2) +2xy +(2y^2 -y^2)`

`= x^2 +2xy +y^2`

`=(x+y)^2`

29 tháng 10 2023

A = \(x^2\) + 2\(xy\) - 3\(x^2\) + 2y2 + 3\(x^2\) - y2

A = (\(x^2\)- 3\(x^2\) + 3\(x^2\)) + 2\(xy\) + (2\(y^2\) - y2)

A = \(x^2\) + 2\(xy\) + y2

A = (\(x\) + y)2

 

29 tháng 10 2023

Kết quả là 1638

 

29 tháng 10 2023

   3 x 3 x 49 + 90 x 13 + 21 + 6

= 9 x 49 + 1170 + 27

= 441 + 1170 + 27

= 1611 + 27

= 1638

 

 

29 tháng 10 2023

1 Mark Twan was born in Missouri in 1835

2 The lesson is so difficult that nobody can understand it

3 A man who is called a tax collector collects taxes

29 tháng 10 2023

1. She was so lazy that she was punished by her teacher.

2. Alice started playing tennis 2 years ago.

3. My uncle is a famous stamp collector.

4. Can I meet you at between 8 am and 9 am?

5. Can you wait for me for a while?

29 tháng 10 2023

1. She was so lazy that she was punished by her teacher.

2. Alice started playing tennis 2 years ago.

3. My uncle is a famous stamp collector.

4. Can I meet you at between 8 am and 9 am?

5. Can you wait for me for a while?

các truyền thống : đoàn kết , tương thân tương ái, yêu nước, ..

29 tháng 10 2023

các truyền thống : đoàn kết , tương thân tương ái, yêu nước, ..

28 tháng 10 2023

Aha! Câu trả lời chính xác nhất đó là con cá. Bây giờ bạn phải đưa tôi 5 coin đi! 

28 tháng 10 2023

Aha! Câu trả lời chính xác nhất là con cá. Bây giờ bạn phải đưa tôi 5 coin ngay đi!

Exercise 7: Choose the best answer to complete the following passage. The Railway System The railway system (1) _____________ in England in the 1820s and became one of the (2) _____________ successful methods of transportation. The railway was practical and connected 3) _____________ of Europe for transport of people and products for over 100 years. They replaced the wagons drawn (4) _____________ horses, and as time passed, the companies and inventors responsible for the railways improved...
Đọc tiếp

Exercise 7: Choose the best answer to complete the following passage.

The Railway System

The railway system (1) _____________ in England in the 1820s and became one of the (2) _____________ successful methods of transportation. The railway was practical and connected 3) _____________ of Europe for transport of people and products for over 100 years. They replaced the wagons drawn (4) _____________ horses, and as time passed, the companies and inventors responsible for the railways improved the trains and the (5) _____________. For the growing United States, the railways presented the only option to connect the already established Eastern coast with the settler and budding towns in the Midwest and West.

(Source: https://www.historyforkids.net/)

1. A. began

B. begin

C. beguns

D. beginning

2. A. more

B. most

C. least

D. so

3. A. much

B. few

C. little

D. some

4. A. for

B. by

C. of

D. on

5. A. tracks

B. roads

C. paths

D. ways

3
28 tháng 10 2023

1 A

2 B

3 A

4 B

5 C

28 tháng 10 2023

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