`(x+1)/2 = (y+3)/4 = (z+5)/6 = (2x + 2)/4 = (4z + 20)/24`

Áp dụng t/chất dãy tỉ số bằng nhau: 

`=> (x+1)/2 = (y+3)/4 = (z+5)/6 = (2x + 2)/4 = (4z + 20)/24 = (2x + 2 + y + 3 -4z - 20)/(4 + 4 - 24) = (-1 + 2 + 3 - 20)/(-16) = (-16)/(-16) = 1`

`=> {((x+1)/2 = 1 -> x = 1 . 2 - 1 = 1),((y+3)/4 = 1 -> y = 1 .4 - 3 = 1),((z+5)/6 = 1-> z = 1.6-5=1)}`

Vậy ...

Đổi `5` tấn `6` tạ `= 5,6` tấn 

Số hàng nhập về trong ngày 2 là: 

`325 xx 2/5 = 130` (tấn) 

Số hàng nhập về trong ngày 3 là: 

`130 + 5,6 = 135,6` (tấn)

Tổng số hàng nhập về là: 

`325 + 130 + 135,6 = 590,6` (tấn)

Đáp số: ....

1. He is reding newspaper.

2. She is brushing her teeth.

3. They are playing football.

4. I am doing my homework.

5. We are going to school.

cho mình 1 đúng nhé

                   Giải:

Các số thỏa mãn đề bài là:

6788; 6878; 6887

7688; 7868; 7886

8678; 8687; 8768; 8786; 8867; 8876

A = {6788; 6878; 6887; 7688; 7868; 7886; 8678; 8687; 8768; 8786;8867;8876}

Diện tích xung quanh của phần chụp đèn là:
Sxq = 1/2 C. d = 1/2 * (4*20) * 22,4 = 896 (cm^2)

a; A =  5\(x^2\) + 10\(xy\) - 4\(x\) - 8y

   A = (5\(x^2\) + 10\(xy\)) - (4\(x\) - 8y) 

  A = 5\(x\).(\(x\) + 2\(y\)) - 4.(\(x+2y\))

 A =  (\(x+2y\)).(5\(x\) - 4)

B = 4\(x^2\) + 4\(x\) - y² + 1

B = (4\(x^2\) + 4\(x\) + 1) - y²

B = [(2\(x\))² + 2.2\(x\).1 + 1²] - y²

B = [2\(x\) + 1]² - y²

B = (2\(x+1\) - y)(2\(x+1\) - y)

Mary's school is near her place

Chọn C nha

Bài 1:

    This is a photo of my family. This is my father. He’s 40 years old. He’s a doctor. And this is my mother. She’s 35. She’s a doctor, too. These are my brother, Tom and my sister, Mary. Tom’s 10 and Mary’s 7. They’re pupils. 

1.     How many people are there in his family?

🡺    ……There are five people in his family……………………………………………………………

2     How old is his father?

🡺    ……His father is 40 years old……………………………………………………………

3.     What does he do?

🡺    ……He is a doctor……………………………………………………………

4.     How old is his mother?

🡺    ……His mother is 35 years old……………………………………………………………

5.     What does she do?

🡺    ……She is a doctor……………………………………………………………

6.     How old is his brother?

🡺    ………His brother is 10 years old…………………………………………………………

7.     How old is his sister?

🡺    ………His sister is 7 years old…………………………………………………………

8.     What do they do?

🡺    ………They are pupils…………………………………………………………

Bài 1:

    This is a photo of my family. This is my father. He’s 40 years old. He’s a doctor. And this is my mother. She’s 35. She’s a doctor, too. These are my brother, Tom and my sister, Mary. Tom’s 10 and Mary’s 7. They’re pupils. 

1.     How many people are there in his family?

🡺    ……There are 5 people in his family……………………………………………………………

2     How old is his father?

🡺    ………He is 40 years old…………………………………………………………

3.     What does he do?

🡺    ……He is a doctor…………………………………………………………

4.     How old is his mother?

🡺    ………She is 35 years old…………………………………………………………

5.     What does she do?

🡺    ……She is a doctor……………………………………………………………

6.     How old is his brother?

🡺    ……He is 10……………………………………………………………

7.     How old is his sister?

🡺    …………She is 7………………………………………………………

8.     What do they do?

🡺    ……………They are pupils……………………………………………………

1 decide

2 adventure

1 decide (âm 2 còn lại âm 2)

2 adventure (âm 2 còn lại âm 1)