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Trần Thanh Loan
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Nguyễn Việt Lâm
7 tháng 5 2023 lúc 23:04

a.

Đặt \(\left\{{}\begin{matrix}\sqrt{x^2+2x+3}=a>0\\\sqrt{x^2+x+2}=b>0\end{matrix}\right.\) \(\Rightarrow a^2-b^2=x+1\)

Pt trở thành:

\(a+b=2\left(a^2-b^2\right)\)

\(\Leftrightarrow a+b=\left(2a-2b\right)\left(a+b\right)\)

\(\Leftrightarrow2a-2b=1\) (do \(a+b>0\))

\(\Leftrightarrow2a=2b+1\)

\(\Leftrightarrow2\sqrt{x^2+2x+3}=2\sqrt{x^2+x+2}+1\)

\(\Leftrightarrow4\left(x^2+2x+3\right)=4\left(x^2+x+2\right)+1+4\sqrt{x^2+x+2}\)

\(\Leftrightarrow4x+3=4\sqrt{x^2+x+2}\)

\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-\dfrac{3}{4}\\16\left(x^2+x+2\right)=\left(4x+3\right)^2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-\dfrac{3}{4}\\8x=23\end{matrix}\right.\) \(\Rightarrow x=\dfrac{23}{8}\)

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Nguyễn Việt Lâm
7 tháng 5 2023 lúc 23:07

b.

ĐKXĐ: \(x\ge3\)

Đặt \(\left\{{}\begin{matrix}\sqrt{x-3}=a\ge0\\\sqrt{x+2}=b>0\end{matrix}\right.\) \(\Rightarrow a^2-b^2=-5\)

Phương trình trở thành:

\(\left(a-b\right)\left(ab+1\right)=a^2-b^2\)

\(\Leftrightarrow\left(a-b\right)\left(ab+1\right)=\left(a-b\right)\left(a+b\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}a=b\left(vô-nghiệm\right)\\ab+1=a+b\end{matrix}\right.\)

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

\(\Leftrightarrow\left(a-1\right)\left(b-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}a=1\\b=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\sqrt{x-3}=1\\\sqrt{x+2}=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=4\\x=-1\left(ktm\right)\end{matrix}\right.\)

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phạm ngọc anh
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Thảo Vy
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Nguyễn Lê Phước Thịnh
19 tháng 12 2021 lúc 23:21

#include <bits/stdc++.h>

using namespace std;

double a;

int main()

{

cin>>a;

if (a>=8.0) cout<<"Gioi";

else if (6.5<=a) cout<<"Kha";

else if (5.0<=a) cout<<"Trung Binh";

else if (3.5<=a) cout<<"Yeu";

else cout<<"Kem";

return 0;

}

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Thảo Vy
Nguyễn Thị Trang
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Sad boy
1 tháng 7 2021 lúc 12:59

THAM KHẢO

 

Câu 1. Thể thơ tự do (kết hợp thể thơ 7 chữ và 8 chữ)

Câu 2. Hình ảnh diễn tả không gian đặc trưng  làng quê:

- bát ngát cánh đồng

- bờ ruộng bùn lấm tấm dấu chân cua

Câu 3. Quê hương có ảnh hưởng nhất định đến lối sống, tính cách, phong cách của mỗi người.

Câu 4. Tình cảm của tác giả đối với quê hương: nhớ thương, trân trọng, biết ơn quê hương của mình

phần làm văn bn tự làm nhé !

 

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Đào kim ngân
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Good boy
4 tháng 5 2021 lúc 17:17

1-c

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Phạm Mạnh Kiên
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ILoveMath
2 tháng 9 2021 lúc 9:06

hình bé quá

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Tử Nguyệt Hàn
2 tháng 9 2021 lúc 9:08

sin 650=cos 350
\(cos70^0=sin30^0\)
\(tan80^0=cot20^0\)
\(cot68^0=tan32^0\)

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Kirito-Kun
2 tháng 9 2021 lúc 9:08

Ko nhìn chữ bn ơi, bn cho to hình một tý

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Nguyễn Ngọc Hương Giang
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jeon jung kook
27 tháng 12 2017 lúc 19:02

LÊN MẠNG TRA CHO NHANH BẠN AH BẠN LÊN MẠNG CHỈ CẦN THAY ĐỔI MỘT ÍT BÀI VĂN LÀ SẼ THÀNH BÀI BAN THÔI  

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๖²⁴ʱČʉէε✦ɠїɾℓ༉
27 tháng 12 2017 lúc 19:13

Bố em làm kĩ sư cơ khí nên có rất nhiều việc phải làm .

Lúc cả nhà đi nghỉ , bố mới  nhẹ nhàng đến bên bàn học của em và cũng là bàn làm việc của bố . Bố bật đèn  bàn học và nhẹ nhàng khởi động máy tính . Tiếng gõ máy tính vang lên lách cách nhưng nhẹ dần khi cả nhà đã đi ngủ . Bố quay sang vẽ hay viết gì đó . Bố đứng dậy lấy mấy cuốn sách để xem .Bố nhíu mày suy nghĩ . Em biết rằng công việc của bố làm tóc bố thêm bạc .Em rất thương bố . Khi xong công việc bố đứng lên vươn vai mấy cái . Chắc bố mệt lắm nhưng sáng mai bố lại là người dậy sớm nhất . 

Công việc của bố em là thế đấy .Em rất quý bố nên quyết tâm học giỏi để bố khỏi phụ lòng .

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Bùi Ngân Nhi
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Trần Đức Huy
3 tháng 2 2022 lúc 17:08

Tham khảo

There is a famous animated film that I think everyone of us has seen at least once, and it is Tom and Jerry. Almost everyone is aware of the story between the miserable Tom and the mischievous mouse Jerry, and it also was part of my childhood memories. The film is about a life under the same roof between two enemies Tom and Jerry, and of course cat and mouse are always hard to get along with. Tom's owner is very afraid mouse, so she always asks Tom to catch the little mouse living in a cave that he digs on the wall. Tom is a quite lazy cat, and he often has to chase Tom so that he is not scolded by his owner or in exchange for a good meal. Sometimes, Jerry also makes mischievous jokes to tease Tom such as pull out his hair or steal his milk. Another character in the movie is the dog Spike, and he does not seem to like Tom at all. In the chasing scenes of the two main characters, they sometimes run to the garden - Spike's residence - and disturb his sleep. Most of the time, Tom would be the one who suffers Spike's anger while Jerry is having a big laugh. The plot is simple but the film Tom and Jerry always attracts a lot of audiences of all ages thanks to the lovely characters and funny circumstances. Although many years have gone by, the television channels have often displayed this film, and this is the indispensable spiritual food children.

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Thư Phan
3 tháng 2 2022 lúc 17:08

Refer

Write about your favourite movie

Today I’d like to talk to you about Harry Porter which is one of my favourite films. It was a fiction film telling a story about people in the wizarding world. The central character was Harry Porter, who used to be an orphan in the normal world before discovering that he was a wizard. Afterwards, he went to a special school called Howard where taught him necessary skills to succeed in wizarding world. He also had to deal with challenges in terms of study, friendship, love and even the fight against dark power.
Harry Porter was recommended as a masterpiece that making me feel curious about it. Moreover, I had read the original novel before, and I really can’t put it down. So I guess the film would be as attractive as the book.
I think the most important reason why I enjoyed this film was that it made me feel adventurous. It was really a fantastic film.

Write about your favourite book

Favorite book and then the series "Doraemon" by Fujiko Fujio. The series told the cat from the future into the past Doremon same friends and help Nobita in the security context miracle. The main character is Doremon with your group Nobita, Shizuka, Xeko, Chaien. Extremely interesting story, engage the reader with the hilarious, witty, and full of magic. But it is also part of suspense through risky adventure of your group. The series is divided into two categories: short stories and novels. I enjoyed the long story, it's about the adventures in a strange land or through time times exciting but dangerous, and the group must go through many difficulties and from there we saw noble friendship bunch of kids. When I read the story I kept imagining myself as the character in that book that I could not put down. And I learned a lot from it especially friendships! If you have not read it try to read offline sure you will like it.

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qlamm
3 tháng 2 2022 lúc 17:11

E tham khảo bài chị viết nhé

Surely everyone knows the movie the wizarding world Harry Potter, right? Of course, it is a movie that has been attached to the childhood of many people. One of my favorites is Harry Potter and the deathly hallows part 2. The film is adapted from the novel of the same name, Harry Potter by author J. K. Rowling. 

Harry Potter was released on July 15, 2011, since its release has won many prestigious awards such as Satellite Award, Saturn Award. Emma Watson, Richard Harris, and Rupert Grint are among the actors who became famous thanks to this movie.

The film tells the journey of the wizard boy Harry Potter and his two best friends, Ron Weasley and Hermione Granger, set at the Hogwarts School of Witchcraft and Wizardry. Movies about the old wizarding world were not known to many people, so when this movie explored the topic of witches, it became more popular. The highlight of the movie is that it was taken at a mystical school of magic, great effects, and a quality cast. 

I highly recommend this film to everybody - the storyline is amazing and the actors act their parts incredibly well - this is a MUST see! The reason I recommend everyone to watch this movie is that the actors here are very good. I think the crew is really lucky to have talented actors to play this movie. The trio of Harry, Hermione, and Ron have created their own brand for Harry Potter. The supporting characters like Snape, Malfoy, and Dumbledore are also great at acting. The film's effects are also a point to help a film become more popular. Do you remember the scene where Hermione and Ron were in the secret room was actually a green curtain behind them. In Goblet of Fire, the actor who plays Harry Potter (Daniel Radcliffe) has to dive into a deep lake to save people, and in real life, he also has to dive into the same lake without any help from the machine. 

The plot is really impressive, helping viewers feel like they are a character in the movie.Not only the movie, but the soundtrack of this movie also became more viral.The soundtrack helps listeners feel thrilling and attractive right from the first time listening. It also became a craze for a while and was made on many online forums.If you are someone who doesn't like watching movies about wizards, then you should watch Harry Potter, because it will change your mind.







 

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