(a-1/9b²)(3a+1/3b²)(3a²+1/27b^4)
=9(a-1/9b²)(a+1/9b²)(a²+1/81b^4)
=9(a²-1/81b^4)(a²+1/81 b^4)
=9a^4-1/729 b^8
在右上角点击【评价】,然后就可以选择【满意,问题已经完美解决】了.
(a-1/9b²)(3a+1/3b²)(3a²+1/27b^4)
=9(a-1/9b²)(a+1/9b²)(a²+1/81b^4)
=9(a²-1/81b^4)(a²+1/81 b^4)
=9a^4-1/729 b^8
在右上角点击【评价】,然后就可以选择【满意,问题已经完美解决】了.