\[\boxed{\mathbf{517}.}\]
\[1)\ \frac{a^{1\frac{1}{2}} \bullet a^{- 0,5}}{a^{\frac{2}{3}}} = \frac{a^{\frac{3}{2}} \bullet a^{- \frac{1}{2}}}{a^{\frac{2}{3}}} =\]
\[= \frac{a^{\frac{3}{2} - \frac{1}{2}}}{a^{\frac{2}{3}}} = \frac{a^{1}}{a^{\frac{2}{3}}} = a^{1 - \frac{2}{3}} = a^{\frac{1}{3}};\]
\[2)\ \frac{a^{- 3} \bullet a^{\frac{7}{3}}}{a^{\frac{1}{3}}} = a^{- 3} \bullet a^{\frac{7}{3} - \frac{1}{3}} =\]
\[= a^{- 3} \bullet a^{\frac{6}{3}} = a^{- 3} \bullet a^{2} =\]
\[= a^{- 3 + 2} = a^{- 1};\]
\[3)\ \left( a^{2,5} \right)^{2} \bullet \sqrt[5]{a} = a^{2,5 \bullet 2} \bullet a^{\frac{1}{5}} =\]
\[= a^{5} \bullet a^{0,2} = a^{5 + 0,2} = a^{5,2};\]
\[4)\ \sqrt[7]{a^{2}} \bullet \left( a^{\frac{3}{14}} \right)^{2} = a^{\frac{2}{7}} \bullet a^{\frac{6}{14}} =\]
\[= a^{\frac{2}{7}} \bullet a^{\frac{3}{7}} = a^{\frac{2}{7} + \frac{3}{7}} = a^{\frac{5}{7}}.\]