87. \(\dfrac{18^5}{2^5\cdot3^9}\).

\(18=2\cdot3^2\), demak:

\(\dfrac{18^5}{2^5\cdot3^9}=\dfrac{2^5\cdot3^{10}}{2^5\cdot3^9}=3^{10-9}=3\).

Javob: 3.