\[\boxed{\text{697\ (697).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[x^{6} + 3x^{2}y^{2} + y^{6} =\]
\[= \left( x^{6} + y^{6} \right) + 3x^{2}y^{2} =\]
\[= x^{4} - x^{2}y^{2} + y^{4} + 3x^{2}y^{2} =\]
\[= x^{4} + 2x^{2}y^{2} + y^{4} =\]
\[= \left( x^{2} + y^{2} \right)^{2} = 1^{2} = 1\]
\[Ответ:1.\]