§ Задание 86
\[\boxed{\mathbf{3.86}}\]

\[14 \cdot 6 = 42 \cdot 2\]
\[\frac{14}{42} = \frac{2}{6};\ \ \ \frac{42}{14} = \frac{6}{2};\ \ \frac{2}{14} = \frac{6}{42}.\]
\[\boxed{\mathbf{3.86}}\]

\[14 \cdot 6 = 42 \cdot 2\]
\[\frac{14}{42} = \frac{2}{6};\ \ \ \frac{42}{14} = \frac{6}{2};\ \ \frac{2}{14} = \frac{6}{42}.\]