Ответ:

  1. \(\sqrt{0{,}0036}+\sqrt{25}=0{,}06+5=5{,}06\).

  2. \(3\cdot\sqrt{1{,}21}=3\cdot1{,}1=3{,}3\).

  3. \(0{,}5\sqrt{0{,}04}+\frac{1}{6}\sqrt{144}=0{,}5\cdot0{,}2+\frac{1}{6}\cdot12=0{,}1+2=2{,}1\).

  4. \(\sqrt{\frac{16}{25}}=\frac{\sqrt{16}}{\sqrt{25}}=\frac{4}{5}\).

  5. \(\sqrt{28}\cdot\sqrt{63}=\sqrt{28\cdot63}=\sqrt{1764}=42\).

  6. \(\sqrt{3^4\cdot4^6}=3^2\cdot4^3=9\cdot64=576\).

Ответ: а) 5,06; б) 3,3; в) 2,1; г) 4/5; д) 42; е) 576.