\(\dfrac{2x+3}{3}=\dfrac{3y-2}{6}=\dfrac{2x+6y-1}{5x}\left(1\right)\)

Từ `2` tỉ số đầu , ta áp dụng t/c của DTSBN , ta đc :

\(\dfrac{2x+3}{3}=\dfrac{3y-2}{6}=\dfrac{2x+3+3y-2}{3+6}=\dfrac{2x+3y+1}{9}\left(2\right)\)

Từ `(1);(2)=>`\(\dfrac{2x+6y-1}{5x}=\dfrac{2x+3y+1}{9}\left(3\right)\)

Từ `(3)` ta xét `2` trường hợp :

+, Nếu `2x+3y+1 \ne  0` thì :

`(3)=>5x=9=>x=9/5`

Thay `x=9/5` vào \(\dfrac{2x+3}{3}=\dfrac{3y-2}{6}\), ta đc :

\(\dfrac{2\cdot\dfrac{9}{5}+3}{3}=\dfrac{3y-2}{6}\\ \Rightarrow\dfrac{\dfrac{18}{5}+3}{3}=\dfrac{3y-2}{6}\\ \Rightarrow\dfrac{11}{5}=\dfrac{3y-2}{6}\\ 3y-2=6\cdot\dfrac{11}{5}\\ 3y-2=\dfrac{66}{5}\\ 3y=\dfrac{76}{5}\\ y=\dfrac{76}{16}\)

+, Nếu `2x+3y+1=0` thì :

`(1)=>` \(\dfrac{2x+3}{3}=\dfrac{3y-2}{6}=0\\ \Rightarrow\left\{{}\begin{matrix}2x+3=0\\3y-2=0\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=-\dfrac{3}{2}\\y=\dfrac{2}{3}\end{matrix}\right.\)

Ta có thể giải bài này theo 2 cách sau:

Cách 1: Để tạo thành một đoạn thẳng thì cần 2 điểm.

Để chọn điểm đầu ta có 101 cách chọn từ 101 điểm.

Để chọn điểm thứ 2 ta có 100 cách chọn.

Với 1 đoạn thẳng ta có 2 cách chọn, ví dụ chọn AB hoặc BA đều giống nhau.

Do đó số đoạn thẳng tạo thành từ 101 điểm này là:

101 x 100 : 2 = 5050 (đoạn thẳng).

Cách 2:

Giả sử ta đánh dấu 101 điểm này bằng số thứ tự từ 1 đến 101.

Chọn điểm đầu là điểm số 1, điểm thứ 2 sẽ có 100 cách chọn. Ta có 100 đoạn thẳng.

Chọn điểm đầu là điểm số 2 thì sẽ có 99 cách chọn điểm thứ 2. Có 99 đoạn thẳng trong trường hợp này.

Làm tương tự tới điểm đầu là điểm số 100, điểm thứ 2 là diểm số 101. Có 1 đoạn thẳng được tạo thành.

Tổng số đoạn thẳng được tạo thành từ 101 điểm này là:

1 +2 +3 + ... + 100 = (1+ 100)/2 x 100 = 5050( đoạn thẳng)

Đề yêu cầu gì em?

Lời giải:

Điều kiện: $x\neq 0; -1$

$\frac{x+3}{x+1}-2=\frac{1-x}{x}$
$1+\frac{2}{x+1}-2=\frac{1}{x}-1$

$\frac{2}{x+1}-1=\frac{1}{x}-1$

$\frac{2}{x+1}=\frac{1}{x}$

$\Rightarrow 2x=x+1$
$\Leftrightarrow x=1$ (thỏa mãn)

a. có vấn đề

b.

\(\dfrac{5x^2-3x}{5}+\dfrac{3x+1}{4}< \dfrac{x\left(2x+1\right)}{2}-\dfrac{3}{2}\)

\(\Leftrightarrow20x^2-12x+15x+5< 20x^2+10x-30\)

\(\Leftrightarrow-22x+5x< -30-5\)

\(\Leftrightarrow-17x< -35\)

\(\Leftrightarrow x>\dfrac{35}{17}\)

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

b: x thuộc {0;0,5}

=>x=0 hoặc x=0,5

Khi x=0 thì M=1/0+1=1

Khi x=0,5 thì M=1/0,5+1=1/1,5=2/3

=>M min=2/3 và M max=1

Tham khảo: Harry Potter is one of my favourite movie. This movie becoming my favourite since it has been held on theatre eight years ago. In my opinion, the story is totally awesome. Based on the best seller novel by JK.Rowling, this movie becomes real. I mean that the story is fiction, but it looks real when we see the movie. This movie story tells about Harry Potter, he is a wizard child since he was a baby, but his parents died by the hand of The Dark wizard,Voldemort. So, he had to struggled on his whole life. When he turned to a young boy, Hogwart school of wizard and wizardry sent him a message that he is a student of that school. In there, he learned everything about magic, and also he found his true friendship, Hermione Granger and Ron Weasley. They always helped Harry Potter in everything, whether is right or wrong. They do this all together, happiness or sorrow. Harry Potter also learned how to love his parents, friends, teachers, and everything. When Voldemort comes to kill Harry Potter, Harry against hard to be win. His bestfriend helped him until they comes to chaotic, but they still hold out. With his witchcraft power, his friends help, and their corageous, voldemort got lost. From the story, i learn something about love, friendship, against everything bad, with our courageous and our heart and soul. That's why this movie becoming my favourite ever, because the story is touching, even it's just a fiction story. But it doesn't mind, because we get everything in this movie, the great adventure, and the philosophy of this movie, definitely Harry Potter is my favourite.

TK

 Harry Potter is one of my favourite movie. This movie becoming my favourite since it has been held on theatre eight years ago. In my opinion, the story is totally awesome. Based on the best seller novel by JK.Rowling, this movie becomes real. I mean that the story is fiction, but it looks real when we see the movie. This movie story tells about Harry Potter, he is a wizard child since he was a baby, but his parents died by the hand of The Dark wizard,Voldemort. So, he had to struggled on his whole life. When he turned to a young boy, Hogwart school of wizard and wizardry sent him a message that he is a student of that school. In there, he learned everything about magic, and also he found his true friendship, Hermione Granger and Ron Weasley. They always helped Harry Potter in everything, whether is right or wrong. They do this all together, happiness or sorrow. Harry Potter also learned how to love his parents, friends, teachers, and everything. When Voldemort comes to kill Harry Potter, Harry against hard to be win. His bestfriend helped him until they comes to chaotic, but they still hold out. With his witchcraft power, his friends help, and their corageous, voldemort got lost. From the story, i learn something about love, friendship, against everything bad, with our courageous and our heart and soul. That's why this movie becoming my favourite ever, because the story is touching, even it's just a fiction story. But it doesn't mind, because we get everything in this movie, the great adventure, and the philosophy of this movie, definitely Harry Potter is my favourite.

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.

Vì mai kém tri thức hơn cô giáo 

Hì đùa xíu

Vì bài kiểm tra bắt đầu mốc 0 điểm nên trả lời một câu đúng được 9 điểm trả lời sai trừ 3 điểm thì điểm số chắc chắn chia hết cho 3

Mà 209 không chia hết cho 3

⇒ Mai tính sai

Do 9 và 3 đều chia hết cho 3 nên tổng số điểm phải chia hết cho 3

Mà số 209 không chia hết cho 3

Nên Mai tính sai