Найди значение выражения

1. \(\sqrt{0,81}-\sqrt{20,25}=\) [ ];

2. \(\dfrac{2}{3}\sqrt{0,36}+\sqrt{\dfrac{25}{16}}=\) [ ];

3. \(\sqrt{5^2-3\cdot2^3}=\sqrt{25 -3\cdot8}=\) [ ];

4. \(\sqrt{\sqrt{25}+\sqrt{16}}=\) [ ];

5. \(\dfrac{36}{49}\sqrt{1\dfrac{13}{36}}-\lgroup-\sqrt\dfrac{1}{7}\rgroup^2=\dfrac{36}{49}\sqrt\dfrac{49}{36}-\dfrac{1}{7}=\) [ ];

6. \(\lgroup\dfrac{1}{3}\sqrt{45}\rgroup^2-0,5\sqrt{5\dfrac{19}{25}}=\) [ ].