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3 tháng 5

Hay thế.

Coái gì

2 tháng 5

Không gửi được bạn ơi!

Gửi xong mất lun à!

nhóm động vật không xương sống nhé, chiếm khoảng 95-97%

2 tháng 5

Nhóm động vật có số lượng loài lớn nhất là lớp Insecta (côn trùng). Côn trùng chiếm hơn 80% số loài động vật trên Trái đất, với hàng triệu loài đã được mô tả và còn nhiều loài chưa được phát hiện. Chính vì vậy, nhóm côn trùng được xem là nhóm động vật đa dạng và phong phú nhất về số lượng loài.

2 tháng 5

Đặt nam châm trên miếng xốp rồi thả vào chậu nước, sao cho nam châm nổi trên mặt nước. Nam châm sẽ quay tự do, đến khi nằm cân bằng trên mặt nước thì: + Một đầu của nam châm hướng về phía Bắc ⇒ đó là cực Bắc của nam châm. + Đầu còn lại hướng về phía Nam ⇒ đó là cực Nam của nam châm.

treo nam châm bằng một sợi chỉ ở giữa hoặc đặt nó nổi trên mặt nước (bằng xốp). Khi nam châm ngừng quay tự do, đầu hướng về phía Bắc địa lý là cực Bắc (N), đầu hướng về phía Nam là cực Nam (S)

Exercise 10: 1 The boy said to girl that he would never see her again. 2 He told her that she was his best friend. 3 Johnny told his mother that he didn’t know how to do that exercise. 4 The children said that they were waiting for the school bus. 5 Mary said that her father had died a year before. 6 John said that he finished studying his lesson. 7 Mary told John that she couldn’t go to the movies with him. 8 Mary told her friend that she would expect to see her the following Wednesday. 9...
Đọc tiếp

Exercise 10: 1 The boy said to girl that he would never see her again. 2 He told her that she was his best friend. 3 Johnny told his mother that he didn’t know how to do that exercise. 4 The children said that they were waiting for the school bus. 5 Mary said that her father had died a year before. 6 John said that he finished studying his lesson. 7 Mary told John that she couldn’t go to the movies with him. 8 Mary told her friend that she would expect to see her the following Wednesday. 9 He said that he didn’t know what had happened. 10 She said that she had gone to the doctor the day before. 11 He said that he had a toothache. 12 She said that she would write him a prescription. 13 They said that they were going to the drugstore. 14 He said that he the doctor had given him some pills. 15 She said that she went to the supermarket every day. Exercise 11: 1 She asked where my umbrella was. 2 Martin asked us how we learned English. 3 He asked if I had to do it. 4 The mother asked her daughter where she had been. 5 She asked her boyfriend which dress she should wear. 6 She wanted to know what they were doing. 7 He wanted to know if I was going to the cinema. 8 The teacher wanted to know who spoke English. 9 She asked me how I knew that . 10 My friend asked me where I had met her. Exercise 12: 1 He asked me if I spoke English. 2 She asked me if I was British or American. 3 She asked me if I had got a computer. 4 He wanted to know if I could type. 5 She wanted to know if I had come by train. 7 he asked her if she would be at the party . 8 She asked me if I could meet her at the station. 9hHe asked me if I had seen that car . 10 The mother asked the twins if they had tidied up their room .

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2 tháng 5

\(\rarr\)

Exercise 10:

1. The boy said to the girl that he would never see her again.

2. He told her that she was his best friend.

3. Johnny told his mother that he didn’t know how to do that exercise.

4. The children said that they were waiting for the school bus.

5. Mary said that her father had died a year before.

6. John said that he had finished studying his lesson.

7. Mary told John that she couldn’t go to the movies with him.

8. Mary told her friend that she would expect to see her the following Wednesday.

9. He said that he didn’t know what had happened.

10. She said that she had gone to the doctor the day before.

11. He said that he had a toothache.

12. She said that she would write him a prescription.

13. They said that they were going to the drugstore.

14. He said that the doctor had given him some pills.

15. She said that she went to the supermarket every day.

Exercise 11:

1. She asked where my umbrella was.

2. Martin asked us how we had learned English.

3. He asked if I had to do it.

4. The mother asked her daughter where she had been.

5. She asked her boyfriend which dress she should wear.

6. She wanted to know what they were doing.

7. He wanted to know if I was going to the cinema.

8. The teacher wanted to know who spoke English.

9. She asked me how I knew that.

10. My friend asked me where I had met her.

Exercise 12:

1. He asked me if I spoke English.

2. She asked me if I was British or American.

3. She asked me if I had got a computer.

4. He wanted to know if I could type.

5. She wanted to know if I had come by train.

6. He asked her if she would be at the party.

7. She asked me if I could meet her at the station.

8. He asked me if I had seen that car.

9. The mother asked the twins if they had tidied up their room.

2 tháng 5
Exercise 10: Chuyển sang câu trực tiếp (Direct Speech)
  1. The boy said to the girl: I will never see you again.
  2. He said to her: You are my best friend.
  3. Johnny said to his mother: I don’t know how to do this exercise.
  4. The children said: We are waiting for the school bus.
  5. Mary said: My father died a year ago.
  6. John said: I finished studying my lesson.
  7. Mary said to John: I can’t go to the movies with you.
  8. Mary said to her friend: I will expect to see you next Wednesday.
  9. He said: I don’t know what happened.
  10. She said: I went to the doctor yesterday.
  11. He said: I have a toothache.
  12. She said: I will write you a prescription.
  13. They said: We are going to the drugstore.
  14. He said: The doctor gave me some pills.
  15. She said: I go to the supermarket every day.
Exercise 11: Chuyển sang câu trực tiếp (Direct Speech)
  1. She asked: Where is your umbrella?
  2. Martin asked us: How do you learn English?
  3. He asked: Do you have to do it?
  4. The mother asked her daughter: Where have you been?
  5. She asked her boyfriend: Which dress should I wear?
  6. She asked: What are they doing?
  7. He asked: Are you going to the cinema?
  8. The teacher asked: Who speaks English?
  9. She asked me: How do you know that?
  10. My friend asked me: Where did you meet her?

số lớn nhất có 3 chữ số là: 999

\(\frac13\) số của 999 là: 999 x \(\frac13\) = 333

gọi số cần tìm là a

Theo đề bài, ta có:

a : 5 : 3 = 333

a : 15 = 333

a = 333 x 15

a = 4995

Vậy số cần tìm là 4995

2 tháng 5

Số lớn nhất là 999

giảm đi 3 lần 1/3 . 999 = 333

giảm đi 5 lần 333 . 14 = 4995

Vậy số đó là 4995.

2 tháng 5

S = 1/1.2.3 + 1/2.3.4 + ...+ 1/98.99.100

S = 1/2.(2/1.2.3 + 2/2.3.4 +..+2/98.99.100)

S = 1/2.(1/1.2 - 1/2.3 + 1/2.3 - 1/3.4 + ... + 1/98.99 - 1/99.100)

S = 1/2.(1/1.2 - 1/99.100)

S = 1/2.(1/2 - 1/9900)

S = 1/2.4949/9900

S = 4949/19800

Ta có nhận xét: 2 / [n(n+1)(n+2)] = 1 / [n(n+1)] - 1 / [(n+1)(n+2)] 2S = 2 / (1.2.3) + 2 / (2.3.4) + 2 / (3.4.5) + ... + 2 / (98.99.100)
2S = (1 / 1.2 - 1 / 2.3) + (1 / 2.3 - 1 / 3.4) + (1 / 3.4 - 1 / 4.5) + ... + (1 / 98.99 - 1 / 99.100)
2S = 1 / 1.2 - 1 / 99.100
2S = 1 / 2 - 1 / 9900
2S = 4950 / 9900 - 1 / 9900
2S = 4949 / 9900
S = 4949 / 9900 : 2
S = 4949 / 19800
Vậy S = 4949 / 19800


2 tháng 5

Your breath

2 tháng 5

\(\rarr\)

The answer is "breath" or "air." Even the strongest person cannot hold their breath for more than a few minutes.

Câu trả lời là "hơi thở" hoặc "không khí." Ngay cả người mạnh nhất cũng không thể giữ hơi thở của mình quá vài phút.

3 tháng 5

Bài 1: Thực hiện các phép nhân sau:

a) 3x^2 * (5x^2 - 7x + 4) = 15x^4 - 21x^3 + 12x^2

b) (2x^2 - 5x) * (3x^2 - 2x + 1) = 6x^4 - 4x^3 + 2x^2 - 15x^3 + 10x^2 - 5x = 6x^4 - 19x^3 + 12x^2 - 5x

c) (x^2 - 8x + 1) * (-2x^3) = -2x^5 + 16x^4 - 2x^3

d) (4x^2 + 2x + 1) * (2x - 1) = 8x^3 - 4x^2 + 4x^2 - 2x + 2x - 1 = 8x^3 - 1

e) (3x^5 - 9x^6 + 12x^9) : (3x) = x^4 - 3x^5 + 4x^8

f) (3x^5 - 9x^6 + 12x^9) : (-3x) = -x^4 + 3x^5 - 4x^8

Bài 2: Thực hiện các phép chia sau:

a) (6x^3 - 7x^2 - x + 2) : (2x + 1) = 3x^2 - 5x + 2

b) (2x^4 - 10x^3 - x^2 + 15x - 3) : (2x^2 - 3) = x^2 - 5x + 1

c) (x^3 - 7x + 3 - x^2) : (x - 3) = x^2 + 2x - 1

d) (2x^4 - 3x^3 - 3x^2 - 2 + 6x) : (x^2 - 2) = 2x^2 - 3x + 1

e) (9x^4 - 6x^3 + 15x^2 + 2x - 1) : (3x^2 - 2x + 5) = 3x^2 - 1 (Câu này chia hơi lẻ, đại ca kiểm tra lại đề xem có nhầm số nào không nhé).

f) (9x^5 - 6x^3 + 18x^2 - 35x - 42) : (3x^2 - 7) = 3x^3 + 5x + 6

Bài 3: Cho hai đa thức: A(x) = -4x^2 - 2x - 8 + 5x^3 - 7x^2 + 1 và B(x) = -3x^3 + 4x^2 + 9 + x - 2x - 2x^3.

a) Thu gọn và sắp xếp các hạng tử của mỗi đa thức trên theo lũy thừa giảm dần của biến.

A(x) = (5x^3) + (-4x^2 - 7x^2) - 2x + (-8 + 1) = 5x^3 - 11x^2 - 2x - 7

B(x) = (-3x^3 - 2x^3) + 4x^2 + (x - 2x) + 9 = -5x^3 + 4x^2 - x + 9

b) Tìm đa thức N(x), biết N(x) = A(x) - B(x).

N(x) = A(x) - B(x) = (5x^3 - 11x^2 - 2x - 7) - (-5x^3 + 4x^2 - x + 9) = 10x^3 - 15x^2 - x - 16

3 tháng 5

Bài 1: Thực hiện các phép nhân sau:

\(a) 3x^2 * (5x^2 - 7x + 4) = 15x^4 - 21x^3 + 12x^2 b) (2x^2 - 5x) * (3x^2 - 2x + 1) = 6x^4 - 4x^3 + 2x^2 - 15x^3 + 10x^2 - 5x = 6x^4 - 19x^3 + 12x^2 - 5x c) (x^2 - 8x + 1) * (-2x^3) = -2x^5 + 16x^4 - 2x^3 d) (4x^2 + 2x + 1) * (2x - 1) = 8x^3 - 4x^2 + 4x^2 - 2x + 2x - 1 = 8x^3 - 1 e) (3x^5 - 9x^6 + 12x^9) : (3x) = x^4 - 3x^5 + 4x^8 f) (3x^5 - 9x^6 + 12x^9) : (-3x) = -x^4 + 3x^5 - 4x^8\)

Bài 2: Thực hiện các phép chia sau:

\(a) (6x^3 - 7x^2 - x + 2) : (2x + 1) = 3x^2 - 5x + 2 b) (2x^4 - 10x^3 - x^2 + 15x - 3) : (2x^2 - 3) = x^2 - 5x + 1 c) (x^3 - 7x + 3 - x^2) : (x - 3) = x^2 + 2x - 1 d) (2x^4 - 3x^3 - 3x^2 - 2 + 6x) : (x^2 - 2) = 2x^2 - 3x + 1 e) (9x^4 - 6x^3 + 15x^2 + 2x - 1) : (3x^2 - 2x + 5) = 3x^2 - 1\)

\(f) (9x^5 - 6x^3 + 18x^2 - 35x - 42) : (3x^2 - 7) = 3x^3 + 5x + 6\)

Bài 3: Cho hai đa thức: A(x) = -4x^2 - 2x - 8 + 5x^3 - 7x^2 + 1 và B(x) = -3x^3 + 4x^2 + 9 + x - 2x - 2x^3.

a) Thu gọn và sắp xếp các hạng tử của mỗi đa thức trên theo lũy thừa giảm dần của biến.

\(A(x) = (5x^3) + (-4x^2 - 7x^2) - 2x + (-8 + 1) = 5x^3 - 11x^2 - 2x - 7 B(x) = (-3x^3 - 2x^3) + 4x^2 + (x - 2x) + 9 = -5x^3 + 4x^2 - x + 9\)

b) Tìm đa thức N(x), biết N(x) = A(x) - B(x).

\(N(x) = A(x) - B(x) = (5x^3 - 11x^2 - 2x - 7) - (-5x^3 + 4x^2 - x + 9) = 10x^3 - 15x^2 - x - 16\)

2 tháng 5

adam và eva (gt)

2 tháng 5

ko có căn cứ để chứng minh người xuất hiện đầu tiên trên trái đất.nhg tổ tiên lâu đời nhất của loài người là cá