№15. \(\dfrac{a^{14}\cdot(b^7)^2}{(a\cdot b)^{16}}\)

\((b^7)^2=b^{14}\), а \((ab)^{16}=a^{16}b^{16}\).

\(\dfrac{a^{14}b^{14}}{a^{16}b^{16}}=\dfrac1{a^2b^2}\).

Ответ: \(\dfrac1{a^2b^2}\).