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6 tháng 1 2024

a=\(\dfrac{x^2-2x+1-4}{x^2+2x+1}\)=\(\dfrac{\left(x^2-2x+1\right)-4}{x^2+2x+1}\)=\(\dfrac{\left(x-1\right)^2-4}{\left(x+1\right)^2}\)

=\(\dfrac{\left(x-1-2\right)\left(x-1+2\right)}{\left(x+1\right)^2}\)=\(\dfrac{x-3}{x+1}\)

Ta có 3x-1=0

=> 3x=1

=> x=\(\dfrac{1}{3}\)

thay số(...)

6 tháng 1 2024

phần còn lại tự làm nhé

6 tháng 1 2024

Nowadays, more and more people prefer buying something via the internet to shopping at traditional markets or supermarkets. Nevertheless, in my opinion, shopping online has both negative and positive aspects.

The first advantage of online shopping is that buyers save more time than other ways of shopping. For example, to buy a motorbike, if you go to shops, you can spend all day on asking about price and information of the product. Meanwhile, if you surf the internet, you can get full information about the product in several clicks; especially, it can be sent fully by the selling staff as soon as you visit their websites. In addition, the price of product bought online is usually lower than that of one bought in shops. There are now a great number of website supplying price comparing functions; as a consequence, customers can choose the same products with the best price, so they can save a large amount of not only time but also money. Lastly, people rarely buy low- quality products if they read carefully feedbacks from previous customers. Today, various websites public truly buyers’ comments about their goods, so customers often choose products having the largest number of good comments.

On the other hand, people may buy low- quality products. Many online stores usually hide bad characters of products, but they only show good sides aiming to attract customers’ attention. For instance, once my friend visited a fashion website in which a skirt that she was satisfied with was sold with a reasonable price. She decided to buy it immediately; as a consequence, its length was so short that she could not wear it when she went out. In addition, many people may waste their money on buying unnecessary items because many shops usually recommend customers to buy one more products through attractive advertisements. Especially, buyers’ private information such as ID numbers or bank accounts can be stolen when websites are attacked by hackers. Consequently, their money in bank account can be stolen or their private lives can be annoyed.

Indeed, buying in the online shops has many benefits such as saving time, getting lower prices and receiving high-quality product from reputable stores. Nevertheless, this buying style have some disadvantages, and to avoid these negative points, customers should find out carefully products, stores and payment methods.

13 tháng 2 2024

Shopping in a supermarket has some great advantages. Firstly, it is good for people who like to see and touch things before buying. Before buying new clothes, you can try them on to make sure they fit well. Second, everyone can know the product's expiration date. If the product is expired, they can return the product to the supermarket. Don't worry about bargain, they are fixed price items so you can never do that. Finally, going to the supermarket is still a great choice.

NV
5 tháng 1 2024

a,

Do \(DE||BC\) (gt) \(\Rightarrow BDEC\) là hình thang

Do \(DE||BC\Rightarrow DI||BC\Rightarrow BDIC\) là hình thang

Do \(DE||BC\Rightarrow IE||BC\Rightarrow BIEC\) là hình thang

b.

Do \(DI||BC\Rightarrow\widehat{CBI}=\widehat{BID}\) (so le trong)

Mà \(\widehat{CBI}=\widehat{DBI}\) (do BI là phân giác góc B)

\(\Rightarrow\widehat{DBI}=\widehat{BID}\)

\(\Rightarrow\Delta BDI\) cân tại D

Tương tự ta có \(\widehat{ICB}=\widehat{CIE}\) (so le trong) và \(\widehat{ICB}=\widehat{ICE}\) (do IC là phân giác góc C)

\(\Rightarrow\widehat{CIE}=\widehat{ICE}\Rightarrow\Delta IEC\) cân tại E

c.

Từ câu b, do \(\Delta BDI\) cân \(\Rightarrow DB=DI\)

Do \(\Delta IEC\) cân \(\Rightarrow IE=CE\)

\(\Rightarrow BD+CE=DI+IE=DE\left(đpcm\right)\)

NV
5 tháng 1 2024

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NV
5 tháng 1 2024

\(2xy+5x^2y-x^3y=xy\left(2+5x-x^2\right)\)

4 tháng 1 2024

a)

\(3x\left(x^2+6x+2\right)\)

\(=3x.x^2+3x.6x+3x.2\)

\(=3x^3+18x^2+6x\)

b)

\(\left(x-3\right)\left(x^2+6x+8\right)\)

\(=x\left(x^2+6x+8\right)-3\left(x^2+6x+8\right)\)

\(=x^3+6x^2+8x-3x^2-18x-24\)

\(=x^3+3x^2-10x-24\)

4 tháng 1 2024

Em nghĩ ,là chị xuống lớp 7 hc lại đi là vừa

4 tháng 1 2024

Dữ liệu trên là dữ liệu số ,có sắp xếp được

4 tháng 1 2024

Dữ liệu trên là dữ liệu định lượng