\[\boxed{\mathbf{1393}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\frac{x}{12} = \frac{3}{4}\]
\[4x = 12 \cdot 3\]
\[4x = 36\]
\[x = 9.\]
\[Подставим\ x = 9\ во\ вторую\ \]
\[пропорцию:\]
\[\frac{8}{3} = \frac{y}{x}\]
\[\frac{8}{3} = \frac{y}{9}\]
\[3y = 8 \cdot 9\]
\[y = \frac{8 \cdot 9}{3} = 8 \cdot 3 = 24.\ \]
\[Ответ:x = 9,\ y = 24.\text{\ \ }\]