[tex]N=3^{2005}(3-2)-2\cdot 3^{2004}-\ldots-2\cdot 3^{1004)=[/tex]
[tex]=3^{2005}-2\cdot 3^{2004}-\ldots-2\cdot 3^{1004}=[/tex]
[tex]=3^{2004}(3-2)-2\cdot 3^{2003Î-\ldots-2\cdot 3^{1004)=[/tex]
[tex]=\ldots\ldots\ldots=[/tex]
[tex]=3^{1005}-2\cdot 3^{1004}=3^{1004}(3-2)=3^{1004}=\left(3^4\right)^{251}=81^{251}[/tex]
Ultima cifră este 1.
