\(2n+7⋮2n+1\)
\(\Leftrightarrow2n+1+6⋮2n+1\)
\(\Leftrightarrow6⋮2n+1\)
\(\Leftrightarrow2n+1\inƯ\left(6\right)=\left\{\pm1;\pm3;\pm6\right\}\)
Ta lập bảng xét giá trị
| 2n+1 | -1 | 1 | -3 | 3 | -6 | 6 |
| 2n | -2 | 0 | -4 | 2 | -7 | 5 |
| n | -1 | 0 | -2 | 1 | \(-\frac{7}{2}\) | \(\frac{5}{2}\) |
a) tham khảo https://olm.vn/hoi-dap/detail/66921453823.html
b)....
\(n+5⋮n+2\)
\(\Leftrightarrow n+2+3⋮n+2\)
\(\Leftrightarrow n+2⋮n+2\)
\(\Leftrightarrow3⋮n+2\)
\(\Leftrightarrow n+2\inƯ\left(3\right)=\left\{\pm1;\pm3\right\}\)
Ta lập bảng xét giá trị
| n+1 | -1 | 1 | -3 | 3 |
| n | -2 | 0 | -4 | 2 |
