Решение:
\(\frac{\sqrt{9a^{19}}}{a} = \frac{\sqrt{9} \cdot \sqrt{a^{19}}}{a} = \frac{3 \cdot a^{19/2}}{a} = 3a^{19/2 - 1} = 3a^{17/2}\)
При a = 2:
\(3 \cdot 2^{17/2} = 3 \cdot 2^{8.5} = 3 \cdot 2^8 \cdot \sqrt{2} = 3 \cdot 256 \cdot \sqrt{2} = 768\sqrt{2}\)
Ответ: \(768\sqrt{2}\)