§ Задание 1287
\[\boxed{\mathbf{1287}\mathbf{.}}\]

\[= \frac{- 6b\sqrt{b} - 36b - 54\sqrt{b}}{9 + 6\sqrt{b} + b} =\]
\[= \frac{- 6\sqrt{b} \bullet \left( b + 6\sqrt{b} + 9 \right)}{9 + 6\sqrt{b} + b} = - 6\sqrt{b}\]
\[\boxed{\mathbf{1287}\mathbf{.}}\]

\[= \frac{- 6b\sqrt{b} - 36b - 54\sqrt{b}}{9 + 6\sqrt{b} + b} =\]
\[= \frac{- 6\sqrt{b} \bullet \left( b + 6\sqrt{b} + 9 \right)}{9 + 6\sqrt{b} + b} = - 6\sqrt{b}\]