1,a³ +27
=(a+3)(a²-3a+9)
2,8-m³
=(2-m)(4+2m+m²)
3,-27x³+8
=-(3x-2)(9x²+6x+4)
4,y²（x²－2x)³﹢y²
=y²[(x²-2x)³+1]
=y²(x²-2x+1)(x^4-4x³+4x²+x²-2x+1)
=y²(x-1)²(x^4-4x³+5x²-2x+1)
5,4xy+1-4x²-y²
=1-(4x²-4xy+y²)
=1-(2x-y)²
=(1+2x-y)(1-2x+y)
6,a⁴b+a³b²-a²b²-ab⁴
建议改成a⁴b+a³b²-a²b³-ab⁴
=ab(a³+a²b-ab²-b³)
=ab(a+b)(a²-b²)
=ab(a+b)²(a-b)