1. Cho hình thang ABCD (AB//CD). Đường thẳng a song song với DC, cắt các cạnh AD và BC theo thứ tự tại M và N.

Chứng minh rằng: a) \(\dfrac{AM}{MD}=\dfrac{BN}{NC};\) b)\(\dfrac{AM}{AD}=\dfrac{BN}{BC};\) c)\(\dfrac{DM}{DA}=\dfrac{CN}{CB}.\)

2. Cho hình thang ABCD (AB // CD). Hai đường chéo AC và BD cắt nhau tại O. Đường thẳng a qua O và song song với đáy của hình thang cắt các cạnh bên AD, BC theo thứ tự tại E và F (h.24).

So sánh OE và OF.

Tìm giá trị nhỏ nhất của biểu thức:

a) M=5x²+y²-4xy-2x-2y+2027

b) A=x²-4xy+5y²+10x-22y+28

Chứng minh rằng với mọi số nguyên n thì:

a) (n+3)²-(n-1)² chia hết cho 8

b) n³+11n ⋮ 6 với ∀ n ∈ Z

c) (n+6)²-(n-6)² chia hết cho 24

Trình bày những phong trào đấu tranh tiêu biểu của nhân dân Ấn Độ cuối thế kỷ 19 - đầu thế kỷ 20. Tại sao các cuộc đấu tranh của nhân dân Ấn Độ lại thất bại?

What do you often do after school? In my school, there are a lot of clubs which students can take part in after school hours.

The club that has the biggest number of members is the swimming club called “Blue Dolphins”. I myself love swimming so I am a member of this club. I go to the swimming pool twice a day and swim for about an hour. I’m really interested in swimming breaststroke because it helps me move as fast as I can. I’m also fond of backstroke. I swim backstroke when I want to relax, breathe and let my body float freely. It’s very relaxing.

The second club I would like to mention is the charity club. Its name is “Golden Heart”. Members of the club often do community service. This month, they are conducting a clean-up campaign to protect the environment around the school. They collect trash, clean the toilet area, and grow plants. I am not a Golden Heart’s member, but I participate in their activities whenever I can.

If you can sing, dance or play musical instruments, the musical club “Heartstrings” is definitely for you. The president of the club is Mike, my best friend. He is not only good-looking but also sings beautifully and plays the guitar very well.

In conclusion, we should do as many activities as possible in our free time to have good health and a fresh mind to prepare for lessons in class. Spending all our time studying is not a good idea.

Question. The musical club “Heartstrings” is definitely for the students who ________ 

A. can sing and dance

B. can sing, dance, and play musical instruments

C. can write songs

D. can cook

Find one odd word A, B, C or D.

A. meat

B. milk

C. egg

D. fish

Thực hiện tính:

A. truth

B. will tell

C. will see

D. happy