đề đau bạn?????

Cho tui xin cái đề thì tui ms giúp đc chứ !!!

gọi số cần tìm là \(\overline{xy}\)

ta có hệ

\(\hept{\begin{cases}5x-y=12\\\left(10y+x\right)-\left(10x+y\right)=36\end{cases}}\)

\(\Rightarrow\hept{\begin{cases}5x-y=12\\-9x+9y=36\end{cases}=>\hept{\begin{cases}45x-9y=108\\-45x+45y=180\end{cases}=>\hept{\begin{cases}36y=288\\5x-y=12\end{cases}=>\hept{\begin{cases}y=8\\5x=20\end{cases}}}}}\)

\(\Rightarrow\hept{\begin{cases}y=8\\x=4\end{cases}}\)

zậy số cần tìm là 48

Whenever you find a new word, try to predict the meaning and look up at the dictionary to know the meaning. 

Chắc vậy :)))))

She wouldn't be very happy because she doesn't have any friends.

Chắc vậy :)))))

she wouldn't very sad because 

1. She said  : " I am working at the restaurant and don't care much for it "

2. Minh spends 2 hours on doing his homework everyday.

3. Because it rained heavily, we were late for school.

4. ( câu này phải là it was chứ vì quá khứ mà )  It was bought last year.

5. You know the man who sat next to me at Nam's birthday party last night.

1."I'm working in a restaurant, and don't care much for it."she said.

- She said that she was working in a restaurant and didn’t care much for it.

2. It takes Minh 2 hours to do his homework every day.

- Minh spends 2 hours doing his homework every day.

3. We were late for school because of the heavy rain.

- Because it rained heavily, we were late for school.

4. People say that they bought this shop last year.

- It is said that they bought this shop last year.

5. Do you know the man who sat next to me at Nam’s birthday party last night?

- You know the man who sat next to me at Nam's birthday party last night, don't you?

Bài tham khảo  vì mk mới có lớp 6 :( 

Gọi số hàng mà học sinh khối 9 xếp như bình thường là x (x ∈ N*, hàng)

      số học sinh trong một hàng là y (y ∈ N*, học sinh)

Nếu tăng thêm 2 hàng so với bình thường thì số hàng là x + 2 (hàng)

Nếu giảm mỗi hàng đi 3 bạn thì mỗi hàng sẽ có y - 3 (học sinh)

Nếu tăng thêm 2 hàng so với bình thường và mỗi hàng giảm đi 3 học sinh thì còn dư 6 bạn nên ta có pt:

    (x + 2).(y - 3) = xy - 6

<=> xy - 3x + 2y - 6 = xy - 6

<=> -3x + 2y =0 (1)

Nếu giảm đi 3 hàng so với bình thường thì số hàng là x - 3 (hàng)

Nếu mỗi hàng tăng thêm 6 bạn thì mỗi hàng sẽ có y + 6 (học sinh)

Nếu xếp ít đi 3 hàng và mỗi hàng tăng thê 6 bạn so với bình thường thì vẫn còn 12 chỗ trống nên ta có pt:

   (x - 3).(y + 6) = xy + 12 

<=> xy + 6x -3y -18 = xy + 12

<=> 6x -3y = 30 (2)

Từ (1) và (2) =>\(\hept{\begin{cases}-3x+2y=0\\6x-3y=30\end{cases}}\)

\(< =>\hept{\begin{cases}-6x+4y=0\\6x-3y=30\end{cases}}\)

\(< =>\hept{\begin{cases}y=30\\-3x+2y=0\end{cases}}\)

\(< =>\hept{\begin{cases}y=30\left(TMĐK\right)\\x=20\left(TMĐK\right)\end{cases}}\)

Vậy, số học sinh khối 9 của trường THCS là 20.30 = 600 (học sinh)

600 hoc sinh

1. The sun always (rise) rises in the east. Look, it (rise) is rising!

2. I don't think i (go) will go out tonight. I'm too tired.

3. Where did you (spend) spend your summer holiday last year, Tam?

4. Has your dog ever bitten anyoine? - Yes, he bit a policeman last week.

5. There were many volunteers in Sea Games 22^nd in Viet Nam in 2003.

6. By (work) working day and night he succeeded in (finish) finishing the job in time.

7. Mai (be) was very happy when she (receive) received a letter from her sister this morning. 

8. Would you (join) to join my class next Sunday? We (visit) will visit the local museum.

9. My father (read) is reading now. He always (read) reads a book after dinner.

10. A friend of my brother’s (call) called him last night, but he (not be) wasn't at home. So I (take) took a message for him.

I. Give the correct form of the verbs

1. The sun always (rise) rises in the east. Look, it (rise)! …is rising………………………..

2. I don’t think I (go) am going to go  out tonight. I’m too tired. ………………………..

3. Where did you  spend(spend) your summer holiday last year, Tam? ……………………………..

4. Has Your dog ever (bite) bitten anyone?   - Yes, he (bite) bit a policeman last week.

5. There (be)  were many volunteers in Sea Games 22^nd in Viet Nam in 2003. …………………

6. By (work) working day and night he succeeded in (finish) finishing the job in time. ………………………

7. Mai (be) was very happy when she (receive) received a letter from her sister this morning. ……………

8. Would you lik e (join) joining my class next Sunday? We (visit) will visit the local museum.

9. My father (read)  is reading now. He always (read) reads a book after dinner……………………………

10. A friend of my brother’s (call) called him last night, but he (not be) wasn't at home. So I (take) took a message for him. …………………………………………………..………………………..

Trl :

bạn kia làm đúng rồi nhé 

    hk tốt nhé bạn @

a)ĐKXĐ : x > 0 

P = \(\left(\frac{x-1}{\sqrt{x}}\right):\left(\frac{\sqrt{x}-1}{\sqrt{x}}+\frac{1-\sqrt{x}}{\sqrt{x}\left(1+\sqrt{x}\right)}\right)\)

    = \(\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}}:\frac{1}{\sqrt{x}}.\left(\sqrt{x}-1+\frac{\sqrt{x}-1}{\sqrt{x}+1}\right)\)

    = \(\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}}:\frac{\sqrt{x}-1}{\sqrt{x}}.\left(1-\frac{1}{\sqrt{x}+1}\right)\)

     = \(\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}}:\frac{\left(\sqrt{x}-1\right).\sqrt{x}}{\sqrt{x}}\)

       = \(\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}.\left(\sqrt{x}-1\right)}=\frac{\sqrt{x}+1}{\sqrt{x}}\)

Vậy P = \(\frac{\sqrt{x}+1}{\sqrt{x}}\)

b) x = \(\frac{2}{2+\sqrt{3}}=\frac{2\left(2-\sqrt{3}\right)}{\left(2+\sqrt{3}\right)\left(2-\sqrt{3}\right)}=\frac{2.\left(2-\sqrt{3}\right)}{4-3}=4-2\sqrt{3}=\left(\sqrt{3}-1\right)^2\)

\(\Rightarrow\sqrt{x}=\sqrt{3}-1\)

=> P = \(\frac{\sqrt{x}+1}{\sqrt{x}}=\frac{\sqrt{3}-1+1}{\sqrt{3}-1}=\frac{\sqrt{3}}{\sqrt{3}-1}\)

        = \(\frac{\sqrt{3}\left(\sqrt{3}+1\right)}{\left(\sqrt{3}-1\right)\left(\sqrt{3+1}\right)}=\frac{3+\sqrt{3}}{3-1}=\frac{3+\sqrt{3}}{2}\)

c)\(P\sqrt{x}=6\sqrt{x}-3-\sqrt{x-4}\)

\(\Leftrightarrow\frac{\left(\sqrt{x}+1\right)\sqrt{x}}{\sqrt{x}}=6\sqrt{x}-3-\sqrt{x-4}\)

\(\Leftrightarrow\sqrt{x}+1=6\sqrt{x}-3-\sqrt{x-4}\)

\(\Leftrightarrow\sqrt{x-4}=5\sqrt{x-4}\)

Đặt \(\hept{\begin{cases}a=\sqrt{x}\\b=\sqrt{x-4}\end{cases}\Rightarrow a^2+b^2=x-\left(x-4\right)=4}\)

\(\Rightarrow\hept{\begin{cases}a^2-b^2=4\\b=5a-4\end{cases}\Rightarrow\hept{\begin{cases}a^2-\left(5a-4\right)^2=4\left(^∗\right)\\b=5a-4\end{cases}}}\)

Từ (*) <=> a² -(25a² -40a + 16 ) =4

        <=>  -24a² + 40a - 20        = 0

=> \(\Delta'=-80< 0\)

=> PT vô nghiệm 

=> ko tồn tại x thỏa mãn

bn lm sai đề bài r