Question

{y^2-3xy=-2

{x^2+5xy=11

Answer 1

$left { {{y^2-3xy=-2,} atop {x^2+5xy=11;}} right. \ y^2-3xy+x^2+5xy=-2+11, \ y^2+2xy+x^2=9, \ (y+x)^2=(pm3)^2, \ left [ {{y+x=-3,} atop {y+x=3;}} right. \ left [ {{y=-3-x,} atop {y=3-x;}} right. \ left [ {{x^2+5x(-3-x)=11,} atop {x^2+5x(3-x)=11;}} right. \ left [ {{-4x^2-15x=11,} atop {-4x^2+15x=11;}} right. \ 4x^2+15x+11=0, D=49, x_1=-1,375, x_2=-0,875; \ 4x^2-15x+11=0, D=49, x_3=0,875, x_4=1,375; \ y_1=-1,625, y_2=-2.125; y_3=2,125, y_4=1,625$