x³-6x²y+12xy²-8y³+1=(x³-8y³)-6xy(x-2y)+1
=(x-2y)(x²+2xy+4y²)-6xy(x-2y)+1
=(x-2y)(x²+2xy+4y²-6xy)+1
=(x-2y)(x²-4xy+4y²)+1
=(x-2y)³+1
x³-6x²y+12xy²-8y³+1=(x³-8y³)-6xy(x-2y)+1
=(x-2y)(x²+2xy+4y²)-6xy(x-2y)+1
=(x-2y)(x²+2xy+4y²-6xy)+1
=(x-2y)(x²-4xy+4y²)+1
=(x-2y)³+1