Ta nhận thấy vế trái có 100 số hạng

=> \(\left(x+x+...+x\right)+\left(1+2+...+100\right)=5500\)

<=> \(100x+\frac{100.101}{2}=5500\)

<=> \(100x+5050=5500\)

<=> \(x=4,5\)

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5550\)

\(< =>x+1+x+2+x+3+...+x+100=5550\)

\(< =>100x+\frac{100\left(100+1\right)}{2}=5550\)

\(< =>100x+\frac{10100}{2}=5550\)

\(< =>100x+5050=5550\)

\(< =>100x=500< =>x=\frac{500}{100}=5\)

Bg

(x + 1) + (x + 2) + (x + 3) +…+ (x + 100) = 5550

(có 100 lần x)

=> 100.x + 1 + 2 + 3 +…+ 100 = 5550

=>  100.x + \(\frac{\left(1+100\right).100}{2}\)= 5550

=> 100.x + 5050 = 5550

=> 100.x = 500

=> x = 5

\(21_{10}=10101_2\)

Chủ đề gì nhii?

The 21st century was a century of science and cone -monks. Therefore, the demand for Gie one of the forms but now, some young people are abusing video games,

As we know, video games are very popular in Vietnam, and Tini countries have advanced to produce electronics when in recent years, they go to work, the number of participants also play is also Not small. Not only in urban areas, although it is the current quota, from adults to young children, male or female because so popular, but the number of curiosity, tu tu and the attractiveness of c GRE GAME WEEKS AUTHER NOT NOT HEALTE OF THE PEOPLE'S PEOPLE'S IN THE GAME, so I continued to play with the time of the action r, causing the situation of the game in the youth. Recently, it has been a number of friends who do not have enough money to play games, CNN made very regrettable mistakes.

As a result, many of you have a number of diseases such as nearsightedness, kimh miraculous disorders, which are the result of weakening learning due to abundant time for games. That not only does it cause trouble with parents and th, but the most warning is the phenomenon

The theft only heals once or twice. Over time, also familiar with the bad nature of their people. The second largest consequence of the video game is leading to many social evils. But we have many modern games that are in the world, but because of the conflict when playing or talking, the two enemies boil the chewing head; That confrontation from a good, gentle person, when the whole ham was not to confirm that it was a lung. The third consequence is also concerned that it is impossible

So where is the phenomenon of the above phenomenon? We do not deny that the electronic world is where that player is the purpose that the soft producers when the video game is attractive by ordinary images, the software manufacturer or the plot select the plot. of comic books, legends, the response of the player will be great. The second Nguyn Nhan is the imagination of the player will be stimulated. But in a game, they will become a brave bank to eliminate and destroy violence as a game today. Also, it is a number of reviews, so for the purpose of all, many people despite the time of the past, sitting hard to stick their eyes on the screen H when they want to play video games is not really,

The phenomena that are not above are also due to the responsibility of parents on many parents who lack the care of their parents and the friends.

BÀI 3:

bài 4:

Là mấy bài này em làm được bài nào chưa?

=23 x (58-30) + 28 x 77

=23 x 28 +28 x 77

=28 x (23+77)

=28 x 100

=2800

học tốt bạn nhé

bài này là dạng nâng cao về toán tính nhanh, mik nghĩ là ẽ ít bạn trả lời đc 

bằng 2800

\(=2.34\left(2+2\cdot2+3\cdot2-2\right)=2.34\cdot10=23.4\)

Tự thân vận động đi hôm nay mik cũng học bài đấy mà đặt tính mà cũng phải hỏi từ lớp 1 rồi đấy 😑 

a: 278157:3=92719

304968:4=76242

mik thấy mấy bài này cũng đơn giản mà,bài nào khó quá thì hỏi cũng đc mà

\(\left(3-x\right)\left(x+1\right)-\left(2.x\right)\left(x+2\right)-3\)

\(=3x+3-x^2-x-2x^2-4x-3=-3x^2-2x\)