解方程组：x平方+xy-2y平方=0 x平方+4y=-2

解,根据x^2 + xy - 2y^2 = 0做因式分解得(x + 2y)(x - y) = 0所以x = y或者x = -2y将x = y代入 x^2 + 4y = -2得y^2 + 4y = -2解得y = -2+根号2 或者 y = -2-根号2将x = -2y代入x^2 + 4y = -2得4y^2 + 4y = -2因为判...