因式分解：1.x^6+y^6－x^4y^2－x^2y^4 2.x^3－8y^3+2x^2+4xy+8y^2

1、原式=(x²+y²)(x^4-x²y²+y^4)-x²y²(x²+y²)
=(x²+y²)(x^4-2x²y²+y^4)
=(x²+y²)(x²-y²)²
=(x²+y²)(x+y)²(x-y)²
2、原式=(x-2y)(x²+2xy+4y²)+2(x²+2xy+4y²)
=(x²+2xy+4y²)(x-2y+2)