\[\boxed{\text{5.272.}}\]
\[\textbf{а)}\ 9\frac{1}{4} = \frac{4 \cdot 9 + 1}{4} = \frac{37}{4}\ \]
\[\textbf{б)}\ 5\frac{6}{7} = \frac{7 \cdot 5 + 6}{7} = \frac{41}{7}\ \]
\[\textbf{в)}\ 2\frac{3}{10} = \frac{10 \cdot 2 + 3}{10} = \frac{23}{10}\ \]
\[\textbf{г)}\ 8\frac{12}{17} = \frac{17 \cdot 8 + 12}{17} =\]
\[= \frac{136 + 12}{17} = \frac{148}{17}\ \]
\[\textbf{д)}\ 11\frac{5}{6} = \frac{6 \cdot 11 + 5}{6} = \frac{71}{6}\ \]