(2a-1)²(1+2a)²(4a²+1)²
=[(2a-1)(1+2a)]²(4a²+1)²
=(4a²-1)²(4a²+1)²
=[(4a²-1)(4a²-1)]²
=(16a^4-1)²
再展开就可以了
=256a^8-32a^4+1