Упрости выражения

1. \(\dfrac{\sqrt{a}+3}{\sqrt{a}-3}-\dfrac{\sqrt{a}+6}{\sqrt{a}}=\) [ ];

2. \(\dfrac{b}{b-25}-\dfrac{\sqrt{b}}{\sqrt{b}+5}=\dfrac{b}{(\sqrt{b}-5)(\sqrt{b}+5)}-\dfrac{\sqrt{b}}{\sqrt{b}+5}=\) [ ];

3. \(\dfrac{4\sqrt{m}-\sqrt{n}}{m+\sqrt{mn}}\cdot \dfrac{2m-2n}{4m-\sqrt{mn}}=\) [ ];

4. \(\dfrac{\sqrt{c}-4}{\sqrt{c}}:\dfrac{c-16}{2c}=\) [ ];

5. \(\left(\dfrac{\sqrt{a}}{\sqrt{a}-\sqrt{b}}+\dfrac{\sqrt{a}}{\sqrt{b}}\right):\dfrac{\sqrt{b}}{\sqrt{b}-\sqrt{a}}=\) [ ];

6. \(\left(\dfrac{\sqrt{c}+7}{\sqrt{c}-7}-\dfrac{\sqrt{c}-7}{\sqrt{c}+7}\right):\dfrac{14}{c-7\sqrt{c}}=\) [ ];

7. \(\dfrac{\sqrt{a}-6}{a+3\sqrt{a}}-\dfrac{\sqrt{a}-3}{\sqrt{a}}+\dfrac{\sqrt{a}}{\sqrt{a}+3}=\) [ ];

8. \(\dfrac{\sqrt{m}+4}{m-6\sqrt{m}+9}:\dfrac{m-16}{2\sqrt{m}-6}-\dfrac{2}{\sqrt{m}-4}=\) [ ].