{3x^2 + 2xy - y^2= 4
{x^2 - 2xy -3y^2 = -4
Сложим
3x^2 + 2xy - y^2 + x^2 - 2xy -3y^2 = 4 - 4
4x^2 - 4y^2 = 0
(x - y)(x + y) = 0
1/ x = y
3x^2 + 2x*x - x^2 = 4
4x^2 = 4
x^2 = 1
x = 1 y = 1
x=-1 y = -1
2/ x = -y
3x^2 - 2x*x - (-x)^2 = 4
0 = 4
решений нет
ответ (1,1) (-1-1)
