Question

{x^2-xy=2 {y^2-xy=-1

Answer 1

Отнимем
x²-y²=3⇒(x-y)(x+y)=3
прибавим
(x-y)²=1
1)x-y=-1
x+y=-3
2x=-4
x=-2
y=-1
2)x-y=1
x+y=3
2x=4
x=2
y=1
(-2;-1);(2;1)