\[\boxed{\text{50\ (50).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\frac{2xy - y^{2}}{3xy + x^{2}} = \frac{y(2x - y)}{x(3y + x)}\]
\[если\ \frac{x}{y} = 2;\ \ то\ x = 2y:\ \ \]
\[\frac{y(2 \cdot 2y - y)}{2y(3y + 2y)} = \frac{3y^{2}}{10y^{2}} = \frac{3}{10} = 0,3.\]
\[\boxed{\text{50.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\frac{2xy - y^{2}}{3xy + x^{2}} = \frac{y(2x - y)}{x(3y + x)}\]
\[если\ \frac{x}{y} = 2;\ \ то\ x = 2y:\ \ \]
\[\frac{y(2 \cdot 2y - y)}{2y(3y + 2y)} = \frac{3y^{2}}{10y^{2}} = \frac{3}{10} = 0,3.\]