-4x³+8x²-4x
=-4x(x²-2x+1)
=-4x(x-1)²
2a的6次方-32a²b的4次方
=2a²(a的4次方-16b的4次方)
=2a²(a²+4b²)(a²-4b²)
=2a²(a²+4b²)(a+2b)(a-2b)
9-(2a+b)²
=[3+(2a+b)][3-(2a+b)]
=(3+2a+b)(3-2a-b)