\[5\frac{1}{7} \cdot (y - 7) - 4\frac{4}{7} \cdot (14 - y) =\]
\[= \frac{36}{7} \cdot (y - 7) - \frac{32}{7} \cdot (14 - y) =\]
\[= \frac{36}{7}y - \frac{36 \cdot 7}{7 \cdot 1} - \frac{32 \cdot 14}{7 \cdot 1} + \frac{32}{7}y =\]
\[= \left( \frac{36}{7} + \frac{32}{7} \right)y - 36 - 64 =\]
\[= \frac{68}{7}y - 100;\]
\[y = - 0,3:\]
\[\frac{68}{7}y - 100 = \frac{68}{7} \cdot ( - 0,3) - 100 =\]
\[= - \frac{68 \cdot 3}{7 \cdot 10} - 100 = - \frac{102}{35} - 100 =\]
\[= - \frac{102}{35} - \frac{3500}{35} = - \frac{3602}{35} =\]
\[= - 102\frac{32}{35}.\]