(2x-1/3)(-1/3-2x)(-1/9-4x^2)=?
问题描述：
(2x-1/3)(-1/3-2x)(-1/9-4x^2)=?
答
(2x-1/3)(-1/3-2x)(-1/9-4x^2)=-(1/3-2x)(1/3+2x)(1/9+4x²)
=-(1/9-4x²)(1/9+4x²)
=-(1/81-16x^4)
=16x^4-1/81