ta có A = \(\frac{1.4}{2.3}+\frac{2.5}{3.4}+....+\frac{98.101}{99.100}=\left(1-\frac{1}{3}\right)+\left(1-\frac{1}{6}\right)+...+\left(1-\frac{1}{4950}\right)\)

\(=\left(1+1+1+...+1\right)-\left(\frac{1}{3}+\frac{1}{6}+....+\frac{1}{4950}\right)\)(có 98 chữ số 1)

 \(=98-\left(\frac{1}{3}+\frac{1}{6}+....+\frac{1}{4950}\right)\)=> A < 98

đi rùi giải tiếp

bạn xem lại đề bài lại hộ mình 3x+5x-7y+30 nhé

ik là đi

ik tức là đi nhưng diễn tả nũng nịu

1.I don't enjoy (laugh)..laughing............at by other people.           

2. I' m angry at him for (tell,not)......not telling.............me the truth.           

3.It is easy (fool)...to fool.....................by his lies.               

4 I expected (invite)..inviting.................to the party ,but I wasn't.

5 somtimes teenagers complain about not ( understand).....understanding........................by their parents.

6.your compositions are supposed (write)...writing...................in ink.

7.loc had a narrow escape.He was almost hit by a car.He barely avoided (hit)..hitting.............by a speeding automobile .

8 Ms thompson is always willing to help if there is a problem in the office ,but she doesn't want (call)...calling..............at home unless there is an emergency.

9.martha dosen't to have her picture taken .She avoids (take).....taking............

10. I appreciate (invite)...inviting........................to your home.  

11.let's not risk (catch)..catching.......................In a traffic jam. 

12 the government tried to stop the book(publish).publishing............ 

13(search)....Searching..............by customs officers is unpleasant.   

14There's a lot of work (do).to do.............

15 the new student hope (include)....including..................in many of the school's social activities

~k nha bạn~

1. being laughed
2. not telling
3. be fooled 
4. to be invited
5. to be understood
6. to be written
7. being hit
8. to be called
9.being taken.
10. to be invited
11.catching
12. publishing 
13. Being searched
14. to do
15. to be included

Chúc cậu học tốt!!!
 

Từ \(5x=2y\Rightarrow\frac{x}{2}=\frac{y}{5}\)

\(3y=5z\Rightarrow\frac{y}{5}=\frac{z}{3}\)

Theo t/c dãy tỉ số "=" nhau :

\(\frac{x}{2}=\frac{y}{5}=\frac{z}{3}=\frac{x+y+z}{2+5+3}=-\frac{970}{10}=-97\)

\(\Rightarrow x=-97.2;y=-97.5;z=-97.3\)

 sssongokusss phiền bạn lần sau đăng câu hỏi linh tinh thì sang trang khác mà đăng nhé. Bạn đăng nhiều qá đè hết lên câu hỏi của bạn khác rồi. Lần sau mong bạn tôn trọng những bạn khác nhé. Mong bạn tuân thủ theo nội quy của olm. Cảm ơn bạn.

Bạn ơi,đừng đăng lung tung,bị khóa tài khoản h!!

Với x = -1

=> M(-1) = 1 - a + b = 0 => a - b = 1

=> M(-2) = 4 - 2a + b = 0 => 2a - b = 4

=> 2a - b - a + b = 4 - 1 = 3

=> a = 3

=> b = 3 - 1 = 2  

x = -1

\(\Rightarrow\)M ( -1 ) = 1 - a + b = 0 \(\Rightarrow\)a - b = 1

\(\Rightarrow\)M ( - 1 ) = 4 - 2a + b = 0 \(\Rightarrow\)2a - b = 4 

\(\Rightarrow\)2a - b - a + b = 4 -1 = 3

\(\Rightarrow\)a = 3          ;         b = 3 - 1 = 2