Упростите выражение: ((n+9)/n-n/(n-9))/(n/(n+9)-(n-9)/n).

\[\frac{\frac{n + 9^{\backslash n - 9}}{n} - \frac{n^{\backslash n}}{n - 9}}{\frac{n^{\backslash n}}{n + 9} - \frac{n - 9^{\backslash n + 9}}{n}} =\]

\[= \frac{\frac{(n + 9)(n - 9) - n^{2}}{n(n - 9)}}{\frac{n^{2} - (n + 9)(n - 9)}{n(n + 9)}} =\]

\[= - \frac{n + 9}{n - 9} = \frac{n + 9}{9 - n}.\]