Question

помогите решить систему уравнений,пожалуйста
x-y+xy=-11,
x-y-xy=1.

Answer 1

$+ left { {{x-y+xy=-11} atop {x-y-xy=1}} right. \ -------- \ 2x-2y=-10 \ x-y=-5 \ x=y-5 \ left { {{x=y-5} atop {y-5-y-(y-5)y=1}} right. = textgreater left { {{x=y-5} atop {-5-y^2+5y=1}} right. = textgreater left { {{x=y-5} atop {-y^2+5y-6=0}} right. = textgreater \ left { {{x=y-5} atop {-(y-2)(y-3)=0}} right. = textgreater left { {{x_1=-3;x_2=-2} atop {y_1=2;y_2=3}} right.$