Ответ:

  1. \(2^{20}\cdot(2^8)^2=2^{20+16}=2^{36}\).
  2. \((11^3)^4:(11^5)^2=11^{12-10}=11^2=121\).
  3. \(7^9\cdot(7^2)^6:7^{19}=7^{9+12-19}=7^2=49\).
  4. \(16^2\cdot8=(2^4)^2\cdot2^3=2^{8+3}=2^{11}=2048\).
  5. \(\frac{10^{17}\cdot(10^2)^3}{(10^3)^4\cdot10^9}=10^{17+6-12-9}=10^2=100\).
  6. \(\frac{9^3\cdot81^2}{3^{12}}=\frac{3^6\cdot3^8}{3^{12}}=3^2=9\).

Ответ: 1) \(2^{36}\); 2) \(121\); 3) \(49\); 4) \(2048\); 5) \(100\); 6) \(9\).