Question

[Nguyễn Mỹ Hoa]

CHO \(A=\frac{n+5}{n+2}\) TÌM GIÁ TRỊ NGUYÊN CỦA n ĐỂ A CÓ GIÁ TRỊ NGUYÊN

Answer 1

[★๖ۣۜßảo๖ۣۜPɦα♏๖ۣۜ[EηgĻïšħ☯€lub]★]

Ta có:\(A=\frac{n+5}{n+2}=\frac{n+2+3}{n+2}=1+\frac{3}{n+2}\)

Để\(A\inℤ\Leftrightarrow\frac{3}{n+2}\inℤ\)

\(\Leftrightarrow n+2\inƯ\left(3\right)=\left\{\pm1;\pm3\right\}\)

\(\Leftrightarrow n=\left\{-1;-3;1;-5\right\}\)

Answer 2

[Upin & Ipin]

DKXD \(n\ne-2\) 

A=\(\frac{n+2+3}{n+2}=1+\frac{3}{n+2}\)  

=> A nguyen<=> \(\frac{3}{n+2}\) nguyen ma n lai la so nguyen theo gt

=> \(\left(n+2\right)\in U\left(3\right)\)

=> n+2 = 1

     n+2=3

     n+2=-1

      n+2=-3

=> n=-1

     n=1 

      n=-3

     n=-5

tatca deu TMDKXD

 Vay \(n\in\left(-5;-3;-1,1\right)\)

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