\[6ab^{5} = - 7\]
\[ab^{5} = - \frac{7}{6}\]
\[6a^{2}b^{10} = 6 \cdot \left( ab^{5} \right)^{2} = 6 \cdot \left( - \frac{7}{6} \right)^{2} =\]
\[= 6 \cdot \frac{49}{36} = \frac{49}{6} = 8\frac{1}{6}.\]