Задача 7: \(\frac{7^4\cdot3^3}{21^2}\)

\[ \frac{7^4\cdot3^3}{21^2}=\frac{7^4\cdot3^3}{(7\cdot3)^2}=7^{4-2}\cdot3^{3-2}=7^2\cdot3=49\cdot3=147. \]

Ответ: 147.