\[\frac{7n^{2} + 3n - 15}{n} =\]
\[= \frac{n(7n + 3) - 15}{n} =\]
\[= \frac{n(7n + 3)}{n} - \frac{15}{n} = 7n + 3 - \frac{15}{n}\]
\[при\ n = 1;3;5;15.\]