10. $$\frac{10n+14}{n^2-49} + \frac{6}{7-n} =$$

$$\frac{10n+14}{n^2-49} + \frac{6}{7-n} = \frac{10n+14}{(n-7)(n+7)} - \frac{6}{n-7} = \frac{10n+14 - 6(n+7)}{(n-7)(n+7)} = \frac{10n+14 - 6n - 42}{(n-7)(n+7)} = \frac{4n - 28}{(n-7)(n+7)} = \frac{4(n-7)}{(n-7)(n+7)} = \frac{4}{n+7}$$ $$\textbf{Ответ: } \frac{4}{n+7}$$