dikun писал(а):
x^2 + 2xy + 2y^2 + 2yz - 2xz + 6z^2 = 1;
(x + y - z)^2 + y^2 + 5z^2 + 4yz = 1;
(x + y - z)^2 + (y + 2z)^2 + z^2 = 1;
z = a,
y + 2z = b,
x + y - z = c,
a^2 + b^2 + c^2 = 1;
1) (a = 1, b = 0, c = 0) => (x = 3, y = -2, z = 1);
2) (a = -1, b = 0, c = 0) => (x = -3, y = 2, z = -1);
3) (a = 0, b = 1, c = 0) => (x = -1, y = 1, z = 0);
4) (a = 0, b = -1, c = 0) => (x = 1, y = -1, z = 0);
5) (a = 0, b = 0, c = 1) => (x = 1, y = 0, z = 0);
6) (a = 0, b = 0, c = -1) => (x = -1, y = 0, z = 0).
все правильно, вот только зачем надо было писать решения с -1?это не правильно я считаю