\[\boxed{\mathbf{866\ (866).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \frac{x^{3k}}{y^{2n}}\ :\frac{x^{6k}}{y^{5n}} = \frac{x^{3k} \cdot y^{5n}}{y^{2n} \cdot x^{6k}} = \frac{y^{3n}}{x^{3k}}\]
\[2)\ \frac{a^{k + 5} \cdot b^{k + 3}}{c^{3k + 2}}\ :\frac{a^{k + 3} \cdot b^{k + 2}}{c^{2k + 1}} =\]
\[= \frac{a^{k} \cdot a^{5} \cdot b^{k} \cdot b^{3} \cdot c^{2k} \cdot c}{c^{3k} \cdot c^{2} \cdot a^{k} \cdot a^{3} \cdot b^{k} \cdot b^{2}} =\]
\[= \frac{a²b}{c^{k} \cdot c} = \frac{a²b}{c^{k + 1}}\]
\[= \frac{x^{n} - 3y^{n}}{x^{2n} - 3x^{n}y^{n} + 9y^{2n}}\]
\[\boxed{\mathbf{8}\mathbf{6}\mathbf{6}\mathbf{\text{.\ }}Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ a - b = 0,4\]
\[a > b.\]
\[2)\ a - b = - 3\]
\[a < b.\]
\[3)\ a - b = 0\]
\[a = b.\]