{x^2-2xy+y^2=1
{x^2+xy-4y^2=2
1 уравнение
(x-y)^2=1 (x-y-1)(x-y+1)=0
x=y+1 или x=y-1
1)поставляем во 2 уравнение
x=y+1
(y+1)^2+(y+1)*y-4y^2=2
y²+2y+1+y²+y-4y²-2=0
-2y²+3y-1=0
2y²-3y+1=0
D=9-8=1
y₁=(3+1)/4=1 x₁=1+1=2
y₂=1/2 x₂=1/2+1=1.5
2)x=y-1
(y-1)^2+(y-1)*y-4y^2=2
y²-2y+1+y²-y-4y²-2=0
2y²+3y+1=0
D=9
y₃=(-3-1)/4=-1 x₃=-1-1=-2
y₄=(-3+1)/4=-1/2 x₄=-1/2-1=-1.5
ответ (-2;-1) (-1.5;-1/2) (2;1) (1.5;1/2)