9. Выполните действия: \(\frac{9m-u}{5m^2u}-\frac{2m+9u}{5mu^2}\).

Общий знаменатель — \(5m^2u^2\):

\[ \frac{9m-u}{5m^2u}-\frac{2m+9u}{5mu^2}=\frac{u(9m-u)-m(2m+9u)}{5m^2u^2}=\frac{9mu-u^2-2m^2-9mu}{5m^2u^2}=-\frac{u^2+2m^2}{5m^2u^2}. \]

Условие: \(m\ne0\), \(u\ne0\).

Ответ: \(-\frac{u^2+2m^2}{5m^2u^2}\).