Решить систему а) xy=-6, x+2 y=-1 б) 5x-7y=31,5x+7y=-11 в) 3x-11y=36,3x+11y=-30

1) {xy=-6{x+2y=-1 {x=-1-2y{y (1+2y)=6{y+2y^2=6{2y^2+y-6=0D=1-4*2*-6=1+48=7^2 y=-1+7/4=3/2y2=-1-7/4=-2x=-4x2=3 2) {5x-7y=31{5x+7y=-11 {5x=31+7y{-11y-7y=31+7y{ -42=14y{y=-3{x=2 3) {3x-11y=36{3x+11y=-30 {3x=36+11y{-30 -11y=36+11y{-66=22y{y=-3{x=1