\(\dfrac{3n+1}{n+1}\)
\(\dfrac{3n+3-2}{n+1}\)
\(\dfrac{3\left(n+1\right)}{n+1}-\dfrac{2}{n+1}\)
\(3-\dfrac{2}{n+1}\)
Để \(\dfrac{3n+1}{n+1}\) đạt nguyên
\(\Leftrightarrow\dfrac{2}{n+1}\)nguyên
\(\Leftrightarrow\left(n+1\right)\in U\left(2\right)=\left\{\pm1;\pm2\right\}\)
Ta có bảng sau:
| n+1 | 1 | -1 | 2 | -2 |
| n | 0(loại) | -2 | 1 | -3 |
Vậy .....................
đề sai
Thiếu nhiều dữ kiện quá bạn eiii!!!
\(\dfrac{a^2+a+3}{a+1}\)
\(\Leftrightarrow\dfrac{a\left(a+1\right)+3}{a+1}\)
\(\Leftrightarrow\dfrac{a\left(a+1\right)}{a+1}+\dfrac{3}{a+1}\)
\(\Leftrightarrow a+\dfrac{3}{a+1}\)
Để \(\dfrac{a^2+a+3}{a+1}\)
\(\Leftrightarrow\left(a+1\right)\in U\left(3\right)=\left\{\pm1;\pm3\right\}\)
Ta có bảng sau:
| a+1 | 1 | -1 | 3 | -3 |
| a | 0 | -2 | 2 | -4 |
Vậy .............
không có x thỏa mãn
No one of the three sisters is younger than Lan.