[tex]\displaystyle\bf\\1)\\\\+\left \{ {{4x-5y=6} \atop {2x+5y=18}} \right. \\---------\\4x-5y+2x+5y=6+18\\\\6x=24\\\\x=24:6=4\\\\5y=18-2x=18-2\cdot 4=18-8=10\\\\y=10:5=2\\\\\\Otvet \ : \ (4 \ ; \ 2)[/tex]

[tex]\displaystyle\bf\\2)\\\\\left \{ {{2x-y=3 } \atop {3x-2y=-8}} \right. \\\\\\\left \{ {{y=2x-3} \atop {3x-2\cdot(2x-3)=-8}} \right. \\\\\\\left \{ {{y=2x-3} \atop {3x-4x+6=-8}} \right. \\\\\\\left \{ {{y=2x-3} \atop {-x=-14}} \right. \\\\\\\left \{ {{y=2\cdot14-3} \atop {x=14}} \right. \\\\\\\left \{ {{y=25} \atop {x=14}} \right. \\\\\\Otvet \ : \ (14 \ ; \ 25)[/tex]