hi quynh nhi,

how are you ?are you having a nice holiday ? i am having a great time  in HA LONG BAY!

it's great weather here ! it's very hot and sunny . my family and i go to the beach every day . the beach is a lot of fun because you can do lots of water sport here . i'm going to waterski this afternoon and my brother is going to windsurf . 

we are going to visit a museum tomorrow morning . it's about the history of halongbay . then later we are going to go shopping in the town . we want to buy some present from halongbay .i want to get you a present in halongbay  . we are goig to fly home next week. i want to show you all my photos! . 

see you soon . 

best wishes, 

thanh xuan

nho k cho mk nhe

Bài 2: 

a: f(8)=3

f(-3)=-8

f(a)=24/a

x²-6y²=1

=>6y²=x²-1

=>y²=\(\frac{x^2-1}{6}\)

Nhận thấy y² là ước của \(\frac{x^2-1}{6}\)

=>y² là số chẵn 

Mà y là số nguyên tố => y=2

=>2²=\(\frac{x^2-1}{6}\)

=>4.6+1=x²

=>25=x²

=>x=5

Vậy y=2 và x=5

2n+6 chia hết cho n+2

=>2n+4+2 chia hết cho n+2

=>2(n+2)+2 chia hết cho n+2

=>2 chia hết cho n+2

=>n+2 \(\in\)Ư(2)={1;2}

n+2=1 (loại)

n+2=2 => n=0

Vậy n={0}

cảm ơn bạn rất nhiều ST *CTV

vì 2n+6 chia hết cho n+2

=>2n+4+2 chia hết cho n+2

=>2(n+2)+2 chia hết cho n+2

=>2 chia hết cho n+2

=>n+2 ∈Ư(2)={1;2}

n+2=1 (loại)

n+2=2 => n=0

Vậy n={0}

Hi Hoa !

here i am at the Superb Summer Camp. Mrs. Huong asks us to write-mail in english. Wow! everything here is in english.

there are 25 kids from different school in Ha Noi. They are all nice and friendly. My new friend is Lien, Phong, Phuc and Linh. This evening we're having a campfire. We're singing and Lien is telling a ghost story! i hope is isn't too scary! tomorrow we're doing a treasure hund in the field. Then in the afernoon we're visiting a milk farm to see how they make milk, cheese and butter. I'm not sure what we're doing on the last day! mrs. Huong hasn't told us yet. I'm sure it will be fun!

i miss you already. please write soon.

Love,

Huyen

Dear Linh,

How are you? I was very happy when I got a letter from you. I am really happy that you spent a wonderful summer holiday in Sa Pa.  And now, I would to tell you about my summer holiday. Last summer I visited Cua Lo beach with my parents. We went there by car. We stayed in Binh Minh hotel for a week.

In Cua Lo, we visited a lot of interesting places: Hon Ngu island, Nguyen Su Hoi temple. But the most exciting for me was visiting Hon Ngu island. It  was fantas and roman.. Food in Cua Lo is extremely delicious. I especially felt excited with the courses from seafood such as "cua rang me, chao ngao or mam ruoc"

Cua Lo's people are very friendly and warm. So, my parents and I felt happy very comfortable at home. Well, I told you everything about my holiday. Trang, what places do you want to visit on your next holiday? Why?

I hope to get the answer from you soon.

     Best wishes,

           Mai

Đổi : 6 ha = 60000 m²

Diện tích trồng nhãn là 60000 : 3 x 5 = 100000 m²
 

0,12 x 135 x 4 + 4,8 x 6,5

=16,2 x 4 + 31,2

=64,8+31,2

=96