X^2+3*x*y+y^2=31, x*y-6=0 система, помогите пожалуйста

x^2+3*x*y+y^2=31 x*y=6   (x+y)^2=31-xy=25   (x+y)=5 xy=6      x=2 y=3               x=3 y=2   x+y=-5 xy=6   x=-2 y=-3 x=-3 y=-2

x^2+3*x*y+y^2=31 x*y=6   (x+y)^2+x*y=31 (x+y)^2=25   Решаем 2 системы: x+y=5                             x+y=-5 x*y=6                              x*y=6   x=5-y                               x=-y-5 (5-y)*y=6                        -(5+y)y=6 y^2-5y+6=0                    y^2+5y+6=0 y = 2  x=3                        y=-3    x=-2 y= 3   x=2                        y=-2    x=-3