1、3a^3-6a^2+3a
= 3a(a^2 -2a +1)
=3a(a-1)^2
2、2a^4-32
=2(a^4-16)
=2(a^2+4)(a^2-4)
=2(a^2+4)(a+2)(a-2)
3、（2x+y）（2x-y）-（2x-y）^2
=4x^2 -y^2 - (4x^2+y^2-4xy)
=4xy
4、（x^2+4）^2-16x^2
=x^4 + 8x^2 +16 -16x^2
=x^4 - 8x^2 +16
=(x^2 -4)^2
=(x+2)²(x-2)²
5、x^4-3x^2-4
=(x^2-4)(x^2+1)
=(x+2)(x-2)(x^2+1)
肯定对,有什么不明白可以继续问,随时在线等.