\[\boxed{\text{712\ (712).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ x^{4} - 16 =\]
\[= \left( x^{2} - 4 \right)\left( x^{2} + 4 \right) =\]
\[= (x - 2)(x + 2)(x^{2} + 4)\]
\[2)\ y^{8} - 1 =\]
\[= \left( y^{4} - 1 \right)\left( y^{4} + 1 \right) =\]
\[= \left( y^{2} - 1 \right)\left( y^{2} + 1 \right)\left( y^{4} + 1 \right) =\]
\[= (y - 1)(y + 1)(y^{2} + 1)(y^{4} + 1)\]