[tex]\displaystyle\bf\\\left \{ {{2x-y=3} \ | \cdot(-2)\atop {3x-2y=-8}} \right. \\\\\\+\left \{ {{-4x+2y=-6} \atop {3x-2y=-8}} \right. \\----------\\-x=-14\\\\x=14\\\\y=2x-3=2\cdot 14-3=28-3=25\\\\Otvet: \ \Big(14 \ ; \ 25\Big)\\\\\\x-y=14-25=-11\\\\\\\boxed{x-y=-11}[/tex]