{4х+3у=5 {х-у=3 {х-у=7 {5х-3у=1 {6х+5у=6 {2х+у=-2

Решение:{х-у=7;         {x=7+y;            {x=7+y;{ху=-10;       {y(7+y)=-10;     {y²+7y+10=0; y²+7y+10=0;D=49-40=3²;y₁=(-7-3)/2=-5;y₂=(-7+3)/2=-2; x₁=7+y₁=7-5=2;x₂=7+y₂=7-2=5; ответ:(2;-5)U(5;-2).