1+3+5+7+...+x=1600(x thuộc N)

[(x-1):2+1].(x+1)/2=1600

(1/2.x-1/2+1).(x+1)=1600:1/2

(1/2.x-1/2+1).(x+1)=3200

(x+1)².1/2=3200

(x+1)²=3200:1/2

(x+1)²=6400

x+1=80

x=80-1=79

21/20

36/25

3/5 : 4/7 = 21/20

6/5 : 5/6 = 36/25

21/20

36/25

Tim x€n

a.72.2-6.(2x+5)=10^5:10^3

b.(5x+3^4).6^8=6^9.3^4

1. I want to meet your mother, it is she.

2.Nam not smart enough to do it.

3. The farmers had not used the modern equipment.

4. My father let me drive the car.

5. She had told me when I was young folk.

6. It is dangerous for children to play in the kitchen.

7. There was a lazy student in my class.

1. I want to meet your mother, it was her.

2.Nam not smart enough to do it.

3.Nguoi farmers have not used the modern equipment.

4. The Ministry of me let me drive the car.

5.Ba I used to tell stories when I was young folk.

6.That is dangerous for children to play in the kitchen.

7.Da been lazy students in my class.

bạn ơi đừng kb với quang diên nha

362924

Ta có : 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 x 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 = 362924

Đ/s : 36292 ❣...❣

     Tk và kb nha ^o^

1.2.3.4...9=362880

1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9

362880