\[\boxed{\mathbf{2.}\mathbf{149}}\]
Пояснение.
Решение.
\[\textbf{а)}\ НОК(65,\ 50,\ 650) = 650\]
\[\frac{9}{65} = \frac{90}{650};\ \ \frac{21}{50} = \frac{21 \cdot 13}{50 \cdot 13} =\]
\[= \frac{273}{650};\ \ \frac{11}{650}.\]
\[\textbf{б)}\ \ 147 = 3 \cdot 7 \cdot 7;\ \ \]
\[63 = 3 \cdot 3 \cdot 7;\ \ 55 = 5 \cdot 11\]
\[\frac{32}{63} = \frac{32 \cdot 385}{63 \cdot 385} = \frac{12320}{24255};\ \ \frac{7}{147} =\]
\[= \frac{7 \cdot 165}{147 \cdot 165} = \frac{1155}{24255};\]
\[\ \frac{41}{55} = \frac{41 \cdot 441}{55 \cdot 441} = \frac{18081}{24255}.\]
\[\textbf{в)}\ НОК(15,\ 12,\ 60) = 60\]
\[\frac{11}{15} = \frac{44}{60};\ \ \frac{7}{12} = \frac{35}{60};\ \ \frac{37}{60}.\]
\[\textbf{г)}\ \]
\[\frac{71}{108} = \frac{710}{1080};\ \ \frac{23}{72} = \frac{23 \cdot 15}{72 \cdot 15} =\]
\[= \frac{345}{1080};\ \frac{47}{90} = \frac{47 \cdot 12}{90 \cdot 12} = \frac{564}{1080}.\]