n^3-n^2+2 / n-1

CMR nếu 3 số x, y, z thoả mãn (x+1)(y+1)(z+1)=(x-1)(y-1)(z-1) thì có thể suy ra được xy+xz+yz=-1

I. There is one mistake in the line marked with a number in the following passage. Underline and correct it:

Spring is the time when there is many festivals in our country. 1. ...............

Among them, Hoa Ban Festival is a most beautiful and interesting, 2. ...............

and it takes place in Lai Chau. It is typical of the cultural life of the 3. ................

Thai people.

In the secong lunar month of the year, when it get warmer and hoa 4. .................

ban - a kind of beautifully flower in the northwest mountainous area - 5. .................

blossoms, Hoa Ban Festival is celebrate.

II. Choose the correct answer:

1. Feeling tired, Ba want to bed ........................ usual last night.

A. late than B. less early than C. more early than D. earlier than

2. He doesn't mind ............................. his classmates when they are in a trouble.

A. helping B. to help C. helped D. help

III. Do as directed in the bracket.

1. Which/ film/ you/ like/ better./ Doraemon/ The Oggy/ ?

_______________________________________________________________________

2. The population of the Bru - Van Kieu is about 74,500 people. (rewrite the sentence)

The Bru - Van Kieu _______________________________________________

3. Which is the most important subject at schools in Viet Nam? (rewrite the sentence)

Which __________________________________________________________________

IV. Write your opinion about life in the countryside ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________