\[\boxed{\mathbf{2.}\mathbf{147}}\]
Пояснение.
Решение.
\[\textbf{а)}\ \frac{3}{7} = \frac{3 \cdot 12}{7 \cdot 12} = \frac{36}{84}\]
\[\textbf{б)}\ \frac{15}{17} = \frac{15 \cdot 8}{17 \cdot 8} = \frac{120}{136}\]
\[\textbf{в)}\ \frac{12}{23} = \frac{12 \cdot 4}{23 \cdot 4} = \frac{48}{92}\]
\[\textbf{г)}\ \frac{10}{11} = \frac{10 \cdot 13}{11 \cdot 13} = \frac{130}{143}\]