11) \(\frac{a-7}{a^2}-\frac{b+2a}{a^2}=\)

\(\frac{(a-7)-(b+2a)}{a^2}=\frac{a-7-b-2a}{a^2}=\frac{-a-b-7}{a^2}\).

Ответ: \(-\frac{a+b+7}{a^2}\)