Tôi có nhiều người bạn thân nhưng thân hơn cả vẫn là nó. Nó mũm mĩm như một trái sim chín, xinh xắn, dễ thương. Nổi bật trên khuôn mặt tròn của nó là đôi mắt đen, to luôn chứa đầy bí ẩn. Nó quý lắm cái mái tóc dài, đen nhánh luôn được cột gọn đằng sau lưng của nó. Tính nó dễ, hay cười ai cũng mến. Nó cũng giản dị vô cùng, bận những chiếc áo đẹp vào những hôm đi chơi còn không thì chỉ một chiếc áo trắng và cái quần âu.  Ngoài ra, nó cũng tốt bụng và học giỏi lắm, nhưng chẳng vì thế mà nó kiêu. Tính nó pha chút đàn ông, tự nhiên, thẳng thắn nhưng rất tình cảm. Tôi quý nó lắm, mong tình bạn chúng tôi mãi bền chặt 😊😊😊

bài 1 :

a)\(2,5.16,27.4+7,3=\left(2,5.4\right).16,27+7,3=10.16,27+7,3\)

\(=162,7+7,3=170\)

b) \(\frac{2}{3}+\frac{3}{4}-\frac{5}{6}=\left(\frac{2}{3}-\frac{5}{6}\right)+\frac{3}{4}=\frac{-1}{6}+\frac{3}{4}=\frac{7}{12}\)

c) \(17,6-5,3+16,8-7,6+15,3-6,8\)

\(=\left(17,6-7,6\right)+\left(-5,3+15,3\right)+\left(16,8-6,8\right)\)

\(=10+10+10=30\)

d)\(\frac{38}{11}+\left(13,16+\frac{6}{11}\right)=\frac{38}{11}+13,16+\frac{6}{11}\)

\(=\left(\frac{38}{11}+\frac{6}{11}\right)+13,16=4+13,16=17,16\)

\(2,45.46+8.0,75+54.2,45+0,5.8\\ =\left[2,45.46+54.2,45\right]\)

\(+\left[8.0,75+0,5.8\right]=\left[2,45.\left(46+54\right)\right]+\left[8.\left(0,75+0,5\right)\right]\)

\(=\left(2,45.100\right)+\left(8.1,25\right)=245+10=255\)

 bài 2 :

a) .....

b) \(1-\left(12,5+x-4,25\right):21,75=0\)

\(\Rightarrow1-\left(12,5+x-4,25\right)=21,75\)

\(\Rightarrow12,5+x-4,25=-20,75\\ \Rightarrow12,5+x=-16,5\)

\(\Rightarrow x=-29\)

cậu có thể tham khảo bài làm trên đây ạ, mn ai thấy đúng thì cho mk xin 1 t.i.c.k đúng ạ ,thank nhiều

Điều kiện là x, y nguyên dương nhé!

Do \(\left(x^2+1\right)\left(x+1\right)=2^y\) nên \(\left(x^2+1\right)=2^m\)và \(x+1=2^n\)với \(m\ge n\), \(m+n=y\)và\(m,n\in N\)

Từ đó ta có: \(x^2+1⋮x+1\Leftrightarrow x^2+x-x-1+2⋮x+1\)

Vậy \(x+1\inƯ\left(2\right)\)nên \(x\in\left\{0;1\right\}\)

Nếu x = 0 thì y = 1

Nếu x = 1 thì y = 2

Đề sai nhiều quá=>Mk k hiểu j cả bạn viết dưới dạng phân số và chép đúng đề bài lại nha

Chúc bạn học tốt

There are four people in my family: my parents, my younger sister and I. My father is a 45-year-old engineer. He spends most of his time in the building sites. That’s why he has a tanned skin. As soon as he comes home, he turns on the television to watch the news, relaxes for a while and then he takes a shower. In case my mother doesn’t cook for the dinner yet, my father is very happy to join hand and help her. Talk about my mother, she is a 40-year-old primary school teacher. In every morning, she is the one who wakes up earliest to prepare the breakfast, clothes and necessary things for my father, me and my sister. After we leave home to work or study, my mother will have a quick breakfast and drive to the primary school. After school, she runs fast to the market, buys some fresh food and backs to home to cook lunch. My father doesn’t come home in the noon so only three of us eat and talk to each other during lunch. However, the lunch is still prepared very scrupulous. In general, my mother is a gentel caring woman and sometimes she is very strict. I have a younger sister who will be 8 years old in the next October. My sister is pretty, docile and hard study. On every weekend, I take her to the park to have fun and we will buy some tasty ice creams. We quite close and sometimes she makes me very angry because of her negligent habit. The last person in my family is me. I am studying in the second year of Business Administration major at Hong Bang University. My schedule is changed frequently and I am also trying to get a scholarship to study abroad in Canada next year so I don’t spend much time to my family. But any time when I am free I try to help my mother in household chorces and take care of my sister. In my family, each person has a different responsibility but we always stand together to enjoy happiness moments, overcome the difficult time and solve the problems. I understand that there is nothing that is more important than my family. I love my parents and my lovely sister so much.

wqerj;jhgfcvnj,..,n dghhmm,bffgf xdfbhbvbnmm 1234ettygvbj776543 

there is a wardrobe next to my beb.

there isn't sofa middle living room.

there is a cat behing the computer.

there are five posters under the table.

There / wardrobe / next to / my beb .

=> There is a wardrobe next to my beb .

There / not / sofa / middle / living room .

=> There is not a sofa in the middle of the living room .

There / cat / behing / computer .

=> There is a cat behing the computer .

There / five posters / under / table .

=> There are five posters under the table .

Học tốt

Đề bạn thiếu 1 số \(x\) nữa đúng không?

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2019}{2021}\)

\(\Rightarrow\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{x\left(x+1\right)}=\frac{2019}{4042}\)

\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x\left(x+1\right)}=\frac{2019}{4042}\)

\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}=\frac{2019}{4042}\)

\(\frac{1}{2}-\frac{1}{x+1}=\frac{2019}{2021}\)

\(\Rightarrow\frac{1}{x+1}=\frac{1}{2021}\)

\(\Rightarrow x+1=2021\)

\(\Rightarrow x=2020\)

Vậy \(x=2020\).

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2019}{2021}\)

\(\Rightarrow2\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{x\left(x+1\right)}\right)=\frac{2019}{2021}\)

\(\Rightarrow\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x\left(x+1\right)}=\frac{2019}{4042}\)

\(\Rightarrow\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}=\frac{2019}{4042}\)

\(\Rightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{2019}{4042}\)

\(\Rightarrow\frac{1}{x+1}=\frac{1}{2}-\frac{2019}{4042}=\frac{1}{2021}\)

\(\Leftrightarrow x+1=2021\)

\(\Leftrightarrow x=2020\left(tm:x\in N\right)\)

Bạn xem lại đề câu thứ nhất nhé!

5 + 9 + 13 + ... + 1997

Số số hạng là: (1997 - 5) : 4 + 1 = 499 (số)

Tổng bằng: (5 + 1997) . 499 : 2 = 499499

Vậy 5 + 9 + 13 + ... + 1997 = 499499.

5 +  9 + 13 + ....... + 1997 + 2001

cảm ơn các bạn

\(5500-375+182=5125+182=5307.\)

\(8376-2453-699=5833-699=5134.\)

\(1054+987-1108=2041-1108=933.\)

\(1540\div11+1890\div9+982=140+210+982=1332.\)

mk cảm ơn các bạn rất nhiều

( x - 35 ) - 120 = 0

⇔ x - 35 = 120

⇔ x = 155

Vậy x = 155

124 + ( 118 - x ) = 217

⇔ 118 - x = 93

⇔ x = 25

Vậy x = 25

156 - ( x + 61)  = 32

⇔ x + 61 = 124

⇔ x = 63

Vậy x = 63