Ta có: 2xy-x+y-2=0

⇔ 2xy-x=2+y

⇔ x.(2y-1)=y+2

⇒ x= \(\frac{y+2}{2y-1}\)

Vì x nguyên nên \(\frac{y+2}{2y-1}\) cũng nguyên.

Ta có: \(\frac{y+2}{2y-1}=\frac{2y+4}{2y-1}=\frac{\left(2y-1\right)+5}{2y-1}=1+\frac{5}{2y-1}\)

Để \(\frac{y+2}{2y-1}\) nguyên thì \(\frac{5}{2y-1}\) nguyên

⇒ 2y-1 ∈ Ư(5) = {-5;-1;1;5}

⇔ y ∈ { -2;0;1;3 }

⇒ x ∈ {0;-4;6;2}

Vậy (x;y)={(0;-2); (-4;0); (6;1); (2;3)}

\(\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+a}>\frac{a}{a+b+c}+\frac{b}{a+b+c}+\frac{c}{a+b+c}\)

\(=\frac{a+b+c}{a+b+c}=1\Rightarrow\)đpcm

2:

a: BC=căn 15^2+20^2=25cm

AH=15*20/25=12cm

góc ADH=góc AEH=góc DAE=90 độ

=>ADHE là hình chữ nhật

=>DE=AH=12cm

b: ΔAHB vuông tại H có HD vuông góc AB

nên AD*AB=AH^2

ΔAHC vuông tại H có HE vuông góc AC

nên AE*AC=AH^2

=>AD*AB=AE*AC

c: góc IAC+góc AED

=góc ICA+góc AHD

=góc ACB+góc ABC=90 độ

=>AI vuông góc ED

4:

a: góc BDH=góc BEH=góc DBE=90 độ

=>BDHE là hình chữ nhật

b: BDHE là hình chữ nhật

=>góc BED=góc BHD=góc A

Xét ΔBED và ΔBAC có 

góc BED=góc A

góc EBD chung

=>ΔBED đồng dạng với ΔBAC
=>BE/BA=BD/BC

=>BE*BC=BA*BD

c: góc MBC+góc BED

=góc C+góc BHD

=góc C+góc A=90 độ

=>BM vuông góc ED

xy-3x+y=10

x(y-3)+y=10

x(y-3)+y-3=7

x(y-3)+(y-3)=7

(x+1)(y-3)=7

=> x+1;y-3 E Ư(7)

Ta có bảng:

Vậy..........................

Sách vien nha

chẳng biết làm gì. giải pt à

Giải pt hay nhân hả bạn??

phương trình

a) Điện trở dây tóc bóng đèn:

\(R=\dfrac{U_{ĐM}^2}{P_{ĐM}}=\dfrac{220^2}{60}=\dfrac{2420}{3}\)(Ω)

3)Công suất bóng đèn lúc này là

\(P_1=\dfrac{U^2_{NG}}{R}=\dfrac{110^2}{\dfrac{2420}{3}}=15\left(W\right)\)

Công suất lúc này đã giảm:

\(P_{ĐM}:P_1=60:15=4\)(lần)

Hello, everybody! My name is Hanh. Today I am here to present to you about Favorite TV shows. I very like watching cartoons. And of all the film I have seen, “Grave of the fireflies” is one in the cartoons which I like most. In Vietnamese it’s called is “Can ham đom đom” or “Mo đom đom”. It’s a tragic story about two childents in the war. It’s made from Japan by Ghibli studio, directed and written by Takahata Isao. It is based on a nover of Nosaka Akiyuki. It’s written as a apologize to his sister. With Japanese, this film is understand as a fable about the respect. Film is been in historical background at the end of the seconds world war from Japan. Film tells a painful story but moving to brothers sentiment of two orphanages : Seita and Setsuko. They lost mother after a fierce bombing of American air force to Kobe city while their father combat for Japanese navy. So Seita and Setsuko must to struggle to exist between the famine and the resistance to merciless of surrounding people (that have their kinship). They have to live in a shelter-pit and often eat frogs and lizards. At the end, Setsuko have to die for hunger, pictures depict painfulness and the death of little girl can be considered as the most mournful film pictures in the cartoon Japan history. When everybody, who had seen this film are asked, most of them said they cried, and that have me. That brings me to the end of my presentation. Many thanks for your attention!

tiếng anh hay việt

One of my favorite TV music shows is The Voice of Vietnam. It is a singing competition on television purchased from the original “The Voice” by Cat Tien Sa and broadcasted in Vietnam starting from July 8, 2012 on VTV3 channel.

I know this program through some means of media such as TV and magazines.

The Voice is rated as one of the most popular entertainment programs. This comes from not only the coaches - the outstanding faces of the entertainment industry but also how to choose contestants attractively.

There are some reasons why 1 like it. Firstly, it’s new and different from other shows. The typical feature of the program is that in the blind audition, in order to select contestants for 4 teams, the coaches will rotate the seats back to the stage and only choose the contestants basing on their singing voice. The program’s criterion that the voice is more concerned than the appearance is considered as the new point and has attracted a large number of viewers. In addition, the coaches are Vietnamese leading singers and composers. They have got a sense of humor and a real enthusiasm for potential young singers, which partially helps them reduce stress.

The show is interesting and it’s worth watching it!

Chúc bạn học tốt! Tick cho mk nhé!❤❤❤