
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.


\(A=\frac{1}{3}.\left(\frac{3}{2.4.6}+\frac{3}{4.6.8}+...+\frac{3}{22.24.26}\right)\)
\(A=\frac{1}{3}.\left(\frac{1}{2.4}-\frac{1}{4.6}+\frac{1}{4.6}-\frac{1}{6.8}+...+\frac{1}{22.24}-\frac{1}{24.26}\right)\)
\(A=\frac{1}{3}.\left(\frac{1}{2.4}-\frac{1}{24.26}\right)\)
\(A=\frac{1}{3}.\frac{77}{624}\)
\(A=\frac{77}{1872}\)

Nhớ rằng: \(\frac{n}{a.\left(a+n\right)}=\frac{1}{a}+\frac{1}{a+n}\)
Ta có: \(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{90}\)
\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{9.10}\)
Áp dụng công thức trên, ta có:
\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}\)
\(A=1-\frac{1}{10}=\frac{9}{10}\)

Odd one out
1. A.scarf B.sandals C.boots D.shoes
2. A.soccer B.tennis C.badminton D.sport
3. A.elephant B.animal C.dolphin D.shark
4. A.play B.seafood C.sandcastle D.beach ball
5.A.violin B.guitar C.music D.piano
6. A.football B.table tennis C.volleyball D.play
7. A.music B.english C.books D.physics
8. A. party B. invite C. complete D. money câu này chịu
9. A.flowers B. visit C. clothes D.sport câu này chịu
10. A. their B. me C. his D. our
11. A. coat B. sandals C. boots D. shoes
11.A.cycle B.ski C.skate D.chess
12.A. giraffe B. seafood C. dolphin D. shark
13.A.play B. badminton C.football D. chess
14. A.english B.music C.subject D.history
nếu sai cho mình xin lỗi
1. A.scarf B.sandals C.boots D.shoes
2. A.soccer B.tennis C.badminton D.sport
3. A.elephant B.animal C.dolphin D.shark
4. A.play B.seafood C.sandcastle D.beach ball
5.A.violin B.guitar C.music D.piano
6. A.football B.table tennis C.volleyball D.play
7. A.music B.english C.books D.physics
8. A. party B. invite C. complete D. money
9. A.flowers B. visit C. clothes D.sport
10. A. their B. me C. his D. our
11. A. coat B. sandals C. boots D. shoes
11.A.cycle B.ski C.skate D.chess
12.A. giraffe B. seafood C. dolphin D. shark
13.A.play B. badminton C.football D. chess
14. A.english B.music C.subject D.history

1. Where do your mother often buy this book? => Where does your mother often buy this book?
2. Are Tom studying? => Is Tom studying?
3. Hoa not have good speaking skill. => Hoa does not have good speaking skill
4. The young girl not writing the letter now. => The young girl is not writing the letter now.
5. Are Lam fond of listening music?=> Is Lam fond of listening to music?
6. They studies math=> They study math
7. What you usually do in the morning? => What do you usually do in the morning?
8. They are traveling to London. => Th ey are travelling to London.
9. The plane is land now.=> The plane is landing now
10. Why she is saying loudly?=> Why is she saying loudly?
1. Where do your mother often buy this book?
=> Where does your mother often buy this book?
2. Are Tom studying English now?
=>Is tom studying English now?
3. Hoa not have good speaking skill.
=>Hoa doesn't have good speaking skill.
4. The young girl not writing the letter now.
=> That young girl isn't writing the letter now.
5. Are Lam fond of listening music?
=> Does Lam fond of listening to music?
6. They studies math once time a week.
=> They study math once time a week.
7. What you usually do in the morning?
=> What do you usually do in the morning?
8. They are traveling to London.
=>They are travelling to London.
9. The plane is land now.
=> The plane is landing now.
10. Why she is saying loudly?
=> why is she saying loudly?
Hok tốt

Bài nghe:
1. How can I get to the bookshop?
(Làm thế nào để tôi có thể đến hiệu sách?)
2. How can I get to the campsite?
(Làm thế nào để tôi có thể đến khu cắm trại?)
Lời giải chi tiết:
1. c 2. a

a.
What are these animals? (Đây là những con vật gì?)
They’re peacocks. (Chúng là những con công.)
I like them. (Tôi thích chúng.)
b.
Why do you like peacocks? (Vì sao bạn thích con công?)
Because they dance beautifully. (Bởi vì chúng múa rất đẹp.)

Bài nghe:
1. A: Would you like some chips? (Cậu muốn chút khoai chiên không?)
B: No, thanks. (Tớ không. Cảm ơn.)
A: What do you want to eat? (Thế cậu muốn ăn gì?)
B: I want some grapes. (Tớ muốn một ít nho.)
2. A: What do you want to eat? (Cậu muốn ăn gì?)
B: I want some jam. (Tớ muốn một ít mứt.)
A: What do you want to drink? (Cậu muốn uống gì?)
B: I want some lemonade. (Tớ muốn chút nước chanh.)
Lời giải:
1. a 2. a

Bài nghe:
1.
A: What's she doing? (Cô ấy đang làm gì vậy?)
B: She's riding a horse. (Cô ấy đang cưỡi ngựa.)
A: Can you ride a horse? (Bạn có thể cưỡi ngựa không?)
B: Yes, I can. (Mình có thể.)
2.
A: Can you play the piano? (Bạn có thể chơi đàn dương cầm không?)
B: No, I can't. (Mình không thể.)
A: Can you play the guitar? (Bạn biết chơi đàn ghi-ta chứ?)
B: Yes, I can. I can do it well! (Mình có. Mình có thể chơi tốt nữa cơ!)
Lời giải:
1. b 2. b

a.
What does your mother do? (Mẹ bạn làm nghề gì vậy?)
She’s a nurse. (Bà ấy là y tá.)
b.
Where does she work? (Bà ấy làm việc ở đâu?)
She works at a nursing home. (Bà ấy làm việc ở viện dưỡng lão.)
3
1+1=2