[tex]\frac{3x-2y}{4x-y}=\frac{3}{7}\Rightarrow \frac{3x-2y}{3}=\frac{4x-y}{7}=k\Rightarrow 3x-2y=3k,4x-y=7k\\
\left \{ {{3x-2y=3k} \atop {4x-y=7k }} \right. \Leftrightarrow \left \{ {{3x-2y=3k} \atop {8x-2y=14k}} \right.\\
11x=17k \Rightarrow x=\frac{17k}{11}\\
4x-y=7k\\
4\cdot \frac{17k}{11}-y=7k\\
\frac{68k}{11}-7k=y\\
y=-\frac{9k}{11}\\
\frac{x}{y}=\frac{\frac{17k}{11}}{-\frac{9k}{11}}=-\frac{17}{9}[/tex]
