Số học sinh giỏi : 50 x 7/50 = 7 học sinh

số học sinh kém : 50 x 1/50 = 1 học sinh 

u viu5uyt778tguyygybg27y-ir87y

B

 Dáp án B

25. Why / you / like / this / programme /?

A. Why does you like this programme?

B. Why do you like this programme?

C. Why you like this programme?

D. Why are you liking this programme?

Put the words /phrases in correct order to make questions.

26. you / practice / table tennis / How often / do / playing /?

A. How often you do practice playing table tennis?

B. How often do you playing table tennis practice?

C. How often do you playing practice table tennis?

D. How often do you practice playing table tennis?

27. you / play / Did / were / when / you / marbles / usually / small /?

A. Did you usually play marbles when were you small?

B. Did you usually played marbles when you were small?

C. Did you usually play marbles when you were small?

D. Did you usually play marbles you were when small?

28. didn’t / He / yesterday / go to class / was / ill / he / because.

A. He was go to school yesterday because he didn’t ill.

B. He didn’t go to class yesterday because he was ill.

C. He was ill because he didn’t go to class yesterday.

D. He didn’t go to class because he was ill.

29. early / tired / she / so /, / was / She / went to bed

A. She went to bed early, so she was tired.

B. She tired, so she was went to bed early.

C. She was tired, so she went to bed early.

D. She was tired, she went to bed early so.

my mom swims very fast

* Trả lời :

My mother has been in Thailand

Sai thì thongcam :)

chắc thêm từ in

my mother in been thailand.

\(5.\left(x+9\right)^2=20\)

\(\Leftrightarrow\left(x+9\right)^2=4\)

\(\Leftrightarrow\orbr{\begin{cases}\left(x+9\right)^2=2^2\\\left(x+9\right)^2=\left(-2\right)^2\end{cases}}\Leftrightarrow\orbr{\begin{cases}x+9=2\\x+9=-2\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-7\\x=-11\end{cases}}\)

K/l : Vậy ...

Sửa lại chỗ này nha:

\(\Leftrightarrow\left(x+9\right)^2=4\)

\(\Leftrightarrow\left(x+9\right)^2=\left(\pm2\right)^2\)

TH1: \(x+9=2\)

\(x=2-9\Leftrightarrow x=-7\)

TH2: \(x+9=\left(-2\right)\)

\(x=\left(-2\right)-9\Leftrightarrow x=-11\)

\(\Rightarrow\orbr{\begin{cases}x=-7\\x=-11\end{cases}}\)