9) \(\frac{81}{49}:6\cdot\frac{42}{51}:\frac{3}{17}=\)

\[\frac{81}{49}:6\cdot\frac{42}{51}:\frac{3}{17}=\frac{81}{49}\cdot\frac{1}{6}\cdot\frac{42}{51}\cdot\frac{17}{3}=\frac{27}{2}\]

Ответ: \(\frac{27}{2}\)