tim n z a) n+4 chia het cho n+2 B) 3n+8 chia het cho n+2

2 bình luận về “tim n z a) n+4 chia het cho n+2 B) 3n+8 chia het cho n+2”

1. a,n+4\vdotsn+2

   =>n+2+2\vdotsn+2

   Vì n+2\vdotsn+2=>2\vdotsn+2

   =>n+2in Ư(2)={+-1;+2}

   Ta có bảng sau:

   $\begin{array}{|c|c|c|}\hline \text{}n+2&\text{}1&\text{}-1&\text{}2&\text{}-2\\\hline \text{}n&\text{}-1&\text{}-3&\text{}0&\text{}-4\\\hline\end{array}$

   Vậy nin{-1;-3;0;-4}

   $\\$

   b,3n+8\vdotsn+2

   =>3(n+2)+2\vdotsn+2

   Vì 3(n+2)\vdotsn+2=>2\vdotsn+2

   =>n+2in Ư(2)={+-1;+2}

   Ta có bảng sau:

   $\begin{array}{|c|c|c|}\hline \text{}n+2&\text{}1&\text{}-1&\text{}2&\text{}-2\\\hline \text{}n&\text{}-1&\text{}-3&\text{}0&\text{}-4\\\hline\end{array}$

   Vậy nin{-1;-3;0;-4}

   Trả lời
2. a) n+4 \vdots n+2

         (n+2)+2 \vdots n+2

   -> n+2 \vdots n+2

   <=> n+2 ∈ Ư(2)

   -> n+2 ∈ {1;-1;2;-2}

   Ta có bảng sau:

   (Hinh ảnh)

   b) 3n+8 \vdots n+2

         (3n+2)+6 \vdots n+2

   -> 3n+2 \vdots n+2

   <=> n+2 ∈ Ư(6)

   -> n+2 ∈ {1;-1;2;-2;3;-3;6;-6}

   Ta có bảng:

   (Hình ảnh)

   $\color{red}{\text{@Hy~Hoctotnha}}$

   

   Trả lời