\[\boxed{\mathbf{2.}}\]
\[1)\ \frac{100}{257} - \left( \frac{21}{257} + \frac{48}{257} \right) =\]
\[= \frac{100}{257} - \frac{21 + 48}{257} =\]
\[= \frac{100 - 69}{257} = \frac{31}{257}\]
\[2)\ \frac{200}{143} - \left( \frac{102}{143} + \frac{26}{143} \right) =\]
\[= \frac{200}{143} - \frac{128}{143} =\]
\[= \frac{200 - 128}{143} = \frac{72}{143}\]
\[\boxed{\mathbf{3.}}\]
\[1)\ x + \frac{5}{12} = \frac{7}{12}\]
\[x = \frac{7}{12} - \frac{5}{12}\]
\[x = \frac{2}{12}.\]
\[2)\ x - \frac{4}{15} = \frac{16}{15}\]
\[x = \frac{16}{15} + \frac{4}{15}\]
\[x = \frac{20}{15}.\]
\[3)\ \frac{13}{17} - x = \frac{4}{17}\]
\[x = \frac{13}{17} - \frac{4}{17}\]
\[x = \frac{9}{17}.\]
\[\mathbf{34.\ Смешанные\ числа}\]
\[\boxed{\mathbf{1.}}\]
\[1)\ \frac{23}{5}:\]
\[23\ :5 = 4\ (ост.\ 3)\]
\[\frac{23}{5} = 4\frac{3}{5}.\]
\[2)\ \frac{40}{7}:\]
\[40\ :7 = 5\ (ост.\ 5)\]
\[\frac{40}{7} = 5\frac{5}{7}.\]
\[3)\ \frac{95}{9}:\]
\[95\ :9 = 10\ (ост.\ 5)\]
\[\frac{95}{9} = 10\frac{5}{9}.\]
\[\boxed{\mathbf{2.}}\]
\[1)\ 3\frac{2}{9} = \frac{9 \cdot 3 + 2}{9} = \frac{29}{9}\]
\[2)\ 4\frac{3}{11} = \frac{11 \cdot 4 + 3}{11} = \frac{47}{11}\]
\[3)\ 1\frac{15}{29} = \frac{29 \cdot 1 + 15}{29} = \frac{44}{29}\]
\[4)\ 5\frac{11}{12} = \frac{12 \cdot 5 + 11}{12} = \frac{71}{12}\]