Răspuns :
[tex]3^{12}\cdot 9^{5}:27^{7}-3^{13}\cdot 9^{6}:27^{8} = \\ \\ =3^{12}\cdot 3^{10}:3^{3\cdot 7}-3^{13}\cdot 3^{12}:3^{3\cdot 8}= \\ \\=3^{12}\cdot 3^{10}:3^{21}-3^{13}\cdot 3^{12}:3^{24}=\\ \\ =3^{12+10-21} - 3^{13+12-24} = \\ \\ = 3^{1} - 3^1 = \\ \\ =\boxed{3}[/tex]