Преобразуем выражение:
$$\frac{n^2-3n}{64n^2-1} : \frac{n^4-27n}{64n^2+16n+1} = \frac{n(n-3)}{(8n-1)(8n+1)} : \frac{n(n^3-27)}{(8n+1)^2} = \frac{n(n-3)}{(8n-1)(8n+1)} \cdot \frac{(8n+1)^2}{n(n^3-27)} = \frac{\cancel{n}(n-3)}{(8n-1)(8n+1)} \cdot \frac{(8n+1)^2}{\cancel{n}(n-3)(n^2+3n+9)} = \frac{8n+1}{(8n-1)(n^2+3n+9)}$$
Ответ: Б) (8n+1)/((8n-1)(n²+3n+9))