Ответ:

  1. \(9^{2/5}\cdot27^{2/5}=(9\cdot27)^{2/5}=243^{2/5}=(3^5)^{2/5}=9\).
  2. \(7^{2/3}\cdot49^{2/3}=(7\cdot49)^{2/3}=343^{2/3}=(7^3)^{2/3}=49\).
  3. \(144^{3/4}:9^{3/4}=(144:9)^{3/4}=16^{3/4}=(2^4)^{3/4}=8\).