Question

{3x+y=-1 {x-xy=8
какой ответ?

Answer 1

$\left \{ {3x+{y=-1} \atop {x-xy=8}} \right.; \left \{ {{y=-1-3x} \atop {x(1-y)=8}} \right.; x(2+3x)=8; 3x^2+2x-8=0; D=4-4*3*(-8)=100=10^2; x=\frac{-2\pm 10  }{2*3} ;\left \{ {{x_{1}=-2} \atop {x_{2}=4/3}} \right.$