解
2a³-8a²+8a
=2a(a²-4a+4)
=2a(a-2)²
a³-4ab²
=a(a²-4b²)
=a(a-2b)(a+2b)
2a(x²+1)²-8ax²
=2a[(x²+1)²-4x²]
=2a[(x²+1)+2x][(x²+1)-2x]
=2a(x+1)²(x-1)²