How often does Nam flies a kite?

Chúc bạn học tốt!

Ta có 6a + 11b chia hết cho 31
Vậy: 6a + 42b - 31b = 6x(a+7b) - 31xb chia hết cho 31
nên: 6x(a + 7b) chia hết cho 31
Do vậy: a + 7b chia hết cho 31 (đpcm)

His sister-in-law is a tall slim woman with long black hair and blue eyes

Playing football on the street is very dangerous for children but they always do that

The Greens get up early in the morning and do aerobics to keep fit

6 His sister - in - law is a tall slim woman with long black hair and blue eyes

7 Playing football on the street is very dangerous for chilren but they always do that

8 The Greens get up early in the morning and do aerobics to keep fit

ta có sơ đồ:On a Friday at school, my friends and I were playing and talking happily when suddenly the teacher came to announce the good news that Tet was coming. arrived. I was surprised because I didn't notice this date until my teacher came to tell me this. Therefore, after knowing the story, I had to run home to help my parent from my parents. cleaning the house to welcome the new year because only tomorrow we will celebrate the new year At the same time, I received a lot of lucky money from everyone and relatives. We visited relatives and brothers in the neighborhood very happily, and together we celebrated New Year's Eve this year, happily and peacefully.
cạn lời quá ghi đại-=))

\(\dfrac{7}{9}+\dfrac{1}{3} < x < \dfrac{43}{8}+\dfrac{1}{10}\)

\(\dfrac{10}{9} < x < \dfrac{219}{40}\)

  Mà \(x \in N\)

  \(=>x=\){`2;3;4;5`}

\(\dfrac{7}{9}+\dfrac{1}{3}< x< \dfrac{43}{8}+\dfrac{1}{10}\)

\(\dfrac{10}{9}< x< \dfrac{219}{40}\)

Mà \(x\inℕ\)

\(\Rightarrow\dfrac{10}{9}< 2\le x\le5< \dfrac{219}{40}\)

\(\Rightarrow2\le x\le5\)

\(\Rightarrow x\in\left\{2;3;4;5\right\}\)

Vậy: \(x\in\left\{2;3;4;5\right\}\)

Người thứ 2 làm xong công việc xong lúc:

  1:1/4=1/4(cong việc)

Người thứ nhất làm xong công việc là:

1:1/3=1/3(công việc)

1 giờ 2 người làm xong số công việc là:

1/4+1/3=7/12(công việc)

Thời gian để 2 người làm xong công việc là:

1:7/12=7/12(công việc)

Đs.........

giúp mình với mình cần gấp

\(4A-3^{2023}\) hay \(4A=3^{2023}\) hả bạn

\(A=1-3+3^2-3^3+...+3^{2021}-3^{2022}\)

\(3A=3-3^2+3^3-3^4+...+3^{2022}-3^{2023}\)

\(3A-A=\left(1-3+3^2-3^3+...+3^{2021}-3^{2022}\right)-\left(3-3^2+3^3-3^4+...+3^{2022}-3^{2023}\right)\)

\(2A=3^{2023}-1\)

\(\Rightarrow A=\left(3^{2023}-1\right)\div2\)

\(\text{cái này mình sợ sai nên bạn có thể nhờ cô chữa}\)

\(\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{12}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}+\dfrac{2}{192}\\ =1+\dfrac{1}{4}+\dfrac{1}{16}+\dfrac{2}{192}\\ =\dfrac{5}{4}+\dfrac{7}{96}=\dfrac{127}{96}\)