(a-2b)(a+2b)(a²+2ab+4b²)(a²-2ab+4b²)
=(a²-4b²) [ (a²+4b²)²-(2ab)² ]
=(a²-4b²) ( a^4+8a²b²+16b^4-4a²b²)
=(a²-4b²) (a^4+4a²b²+16b^4)
=(a²)³-(4b²)³
=a^6-64b^6