Rút gọn các biểu thức sau:

a) A = a(a-b)-b(a-b);

b) B = m ( - 2 m 3   +   1 )   +   m 2 ( 2 m 2   +   1 ) - m ;

c) C = ( - 2 t ) 2 ( t   +   2 ) - 8 t 2 ( 1 - t ) - 4 t 3 .

Rút gọn các biểu thức sau

a) A = - 1 3 y 2 ( 6 y - 3 ) - y y + 1 2 + 1 2 y - 8  

b) B = 3 x n   ( 6 x n - 3   + 1 )   -   2 x n   ( 9 x n - 3   - 1 )  với n là số tự nhiên.

Mark the letter A, B, C, or D to indicate the sentence that best combines each pair of sentences in the following questions.

The company director decided to raise the workers' wages. He did not want them to leave.

A.The company director decided to raise the workers' wages, so they did not leave.

B.The company director decided to raise the workers' wages though he wanted them to leave.

C.The workers did not want to leave since the company director decided to raise their wages.

D.Not wanting the workers to leave, the company director decided to raise their wages.

Bài thơ "Đất nước" được sáng tác trong khoảng thời gian nào?

A.   1948 – 1954

B.   1948 – 1955

C.   1948 – 1956

D.   1948 – 1957

- “Would you bother if I had a look at your paper?” - “……………”

A. You’re welcome

B. Well, actually I’d rather you didn’t

C. That’s a good idea

D. Oh, I didn’t realize that

Choose the letter A, B, C or D to complete the sentences

This area is ________ overcrowding that the price of housing goes up very high.

A. such

B. too

C. so

D. enough

Văn bản “Bài toán dân số” thuộc thể loại gì?