§ Задание 81
\[\boxed{\mathbf{4.}\mathbf{81}}\]
\[\textbf{а)} - a = - 9,123\]
\[a = 9,123.\]
\[\textbf{б)} - z = 4\frac{3}{7}\]
\[z = - 4\frac{3}{7}\text{.\ }\]
\[\boxed{\mathbf{4.}\mathbf{81}}\]
\[\textbf{а)} - a = - 9,123\]
\[a = 9,123.\]
\[\textbf{б)} - z = 4\frac{3}{7}\]
\[z = - 4\frac{3}{7}\text{.\ }\]