Ответ:

  1. \(0.5^8\cdot2^8=(0.5\cdot2)^8=1^8=1\).
  2. \(2^5\cdot5^5=(2\cdot5)^5=10^5=100000\).
  3. \(\left(\frac13\right)^6\cdot6^6=\left(\frac13\cdot6\right)^6=2^6=64\).
  4. \(0.125^9\cdot8^9=(0.125\cdot8)^9=1^9=1\).
  5. \(1\frac79=\frac{16}{9}\), поэтому \(\left(\frac{16}{9}\right)^{11}\cdot\left(\frac{9}{16}\right)^{12}=\left(\frac{16}{9}\right)^{11}\cdot\left(\frac{9}{16}\right)^{11}\cdot\frac{9}{16}=\frac{9}{16}\).
  6. \(0.25^{20}\cdot4^{18}=\left(\frac14\right)^{20}\cdot4^{18}=4^{-20}\cdot4^{18}=4^{-2}=\frac1{16}\).

Ответ: 1) 1; 2) 100000; 3) 64; 4) 1; 5) \(\frac{9}{16}\); 6) \(\frac1{16}\).