Phần trên của bạn Thiện Hi là đúng rồi nhưng đáp án sai , Đáp án đúng là \(\dfrac{155}{233}\) bạn sửa đáp án lại nhé !!!

\(\dfrac{4}{3.5}+\dfrac{4}{5.7}+...+\dfrac{4}{2016.2018}\\ =2.\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{2016}-\dfrac{1}{2018}\right)\\ =2.\left(\dfrac{1}{3}-\dfrac{1}{2018}\right)\\=2.\dfrac{2015}{6054}\\ =\dfrac{2015}{3027} \)

250 cc = 250 ml

= 250 nha bạn

250 cc = 250 ml

 * That building .......is not as high as this building................................................................................

2. No one in my class learns better than Ba.

  * Ba learns............the best in my class................................................................................

3. To learn English is not easy.

  * It is ..not easy to learn English...................................................................................................

4. The film is boring.

  * What a ...........boring film.....................................................................................

5. This man drives carefully.

  * This man is a ...........careful driver...........................................................................

6. She is a good English teacher.

  * She teaches ............well............................................................................

7. I like apples, Lan likes apples.

  *  I like apples so .......does Lan.............................................................................

8. How long is that table?

 * What is the .......length of that table?....................................................................................

9. How much is the green dress?

 * How much does .......the green dress cost?............................................................................

10. Nam doesn't like Math. I don't like it.

  * I don't like Math neither ..........does nam.............................................................

HU                Rewrite the sentences so that the maening stays the same:

1. This building is higher than that building.

 * That building .............................  isn't as high as this building..........................................................

2. No one in my class learns better than Ba.

  * Ba learns............................ the best in my class................................................................

3. To learn English is not easy.

  * It is .................... not easy to learn english.................................................................................

4. The film is boring.

  * What a ...................... boring film !..........................................................................

5. This man drives carefully.

  * This man is a .................... careful driver..................................................................

6. She is a good English teacher.

  * She teaches ............................. english well...........................................................

7. I like apples, Lan likes apples.

  *  I like apples so ...................  does Lan.................................................................

8. How long is that table?

 * What is the .......................... length of that table ?.................................................................

9. How much is the green dress?

 * How much does ..................... the green dress cost ?..............................................................

10. Nam doesn't like Math. I don't like it.

  * I don't like Math neither .............................. does Nam.........................................

* That building .......is not as high as this building................................................................................

2. No one in my class learns better than Ba.

  * Ba learns............the best in my class................................................................................

3. To learn English is not easy.

  * It is ..not easy to learn English...................................................................................................

4. The film is boring.

  * What a ...........boring film.....................................................................................

5. This man drives carefully.

  * This man is a ...........careful driver...........................................................................

6. She is a good English teacher.

  * She teaches ............well............................................................................

7. I like apples, Lan likes apples.

  *  I like apples so .......does Lan.............................................................................

8. How long is that table?

 * What is the .......length of that table?....................................................................................

9. How much is the green dress?

 * How much does .......the green dress cost?............................................................................

10. Nam doesn't like Math. I don't like it.

  * I don't like Math neither ..........does nam.............................................................

Đổi : 1,2dam = 12m

Tổng độ dài hai đáy là :

\(300\times2:12=50\left(m\right)\)

Đáp số : 50m

Đổi : 1,2dam = 12m

Tổng độ dài hai đáy là :

300\times2:12=50\left(m\right)$300\times 2:12=50\left(m\right)$

Đáp số : 50m

1: 

Ta có: \(D=\dfrac{3}{5\cdot7}+\dfrac{3}{7\cdot9}+\dfrac{3}{9\cdot11}+...+\dfrac{3}{53\cdot55}\)

\(=\dfrac{3}{2}\left(\dfrac{2}{5\cdot7}+\dfrac{2}{7\cdot9}+\dfrac{2}{9\cdot11}+...+\dfrac{2}{53\cdot55}\right)\)

\(=\dfrac{3}{2}\left(\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}+...+\dfrac{1}{53}-\dfrac{1}{55}\right)\)

\(=\dfrac{3}{2}\left(\dfrac{1}{5}-\dfrac{1}{55}\right)\)

\(=\dfrac{3}{2}\left(\dfrac{11}{55}-\dfrac{1}{55}\right)\)

\(=\dfrac{3}{2}\cdot\dfrac{2}{11}=\dfrac{3}{11}\)

2) Để A là số nguyên dương thì 

\(\left\{{}\begin{matrix}x+2⋮x-5\\x-5>0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x-5+7⋮x-5\\x>5\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}7⋮x-5\\x>5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x-5\inƯ\left(7\right)\\x>5\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x-5\in\left\{1;-1;7;-7\right\}\\x>5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\in\left\{6;4;12;-2\right\}\\x>5\end{matrix}\right.\)

\(\Leftrightarrow x\in\left\{6;12\right\}\)

Giải:

1)D=3/5.7+3/7.9+3/9.11+...+3/53.55

   D=3/2.(2/5.7+2/7.9+2/9.11+...+2/53.55)

   D=3/2.(1/5-1/7+1/7-1/9+1/9-1/11+...+1/53-1/55)

   D=3/2.(1/5-1/55)

   D=3/2.2/11

   D=3/11

Nguyễn Đào Thuỳ Dương mk k hok qiỏi văn lém , 

Mk chúc bn lm đc 1 bài văn thật hay , đạt đc điểm thật cao nhé

CỐ LÊN !! CỐ LÊN

Mk vỗ chân cổ vũ bn 

Đâu phải làm chuyện gì sai đâu mà bảo là .....trái tim phải không?Nếu chưa có ai giải đáp thì bạn tự làm đi , đợi đến khi có ng trả lời nhé!!

Tỉ số \(6\frac{1}{\frac{5}{5\frac{1}{6}}}\) có thể rút gọn thành \(\frac{6}{5}\).Thử lại: \(6\frac{1}{\frac{5}{5\frac{1}{6}}}\)=\(\frac{31}{\frac{5}{\frac{31}{6}}}\)=\(\frac{31}{5}\).\(\frac{6}{31}\)=\(\frac{6}{5}\)

ta có thể viết tỉ số khác cũng có thể "rút gọn" như vậy:VD: \(1\frac{7}{\frac{9}{2\frac{1}{7}}}\)=\(\frac{7}{8}\)

@@ Đừng buồn bạn nhá luôn có người giúp đỡ bạn !!! ^_^"

Dãy số trên có :

          ( 100 - 1 ) : 1 + 1 = 100 ( số hạng )

Vậy tổng dãy số trên là :

           ( 100 + 1 ) x 100 : 2 = 5050

                                  Đ/s : 5050

phân số nào

1 + 2 +  3 + 4 + ... + 99 + 100

Ta có :

1 + 2 + 3 + 4 + ... + 99 + 100 ( có 100 số hạng )

= (100 + 1) x 100 : 2 = 5050

sai đề hả bn

..

hì

gì cũng khác

2 truyện này rõ rành khác thể loại truyện lại chẳng liên quan gì đến nhaucar hay là đề là tìm điểm giống nhau