Rút gọn 

Q=\(\left(\dfrac{1}{\sqrt{a}-1}-\dfrac{1}{\sqrt{a}}\right):\left(\dfrac{\sqrt{a}+1}{\sqrt{a}-2}-\dfrac{\sqrt{a}+2}{\sqrt{a}-1}\right)\)

Tính \(\dfrac{5\sqrt{5}-2\sqrt{2}}{\sqrt{5}-\sqrt{2}}+5\sqrt{\dfrac{2}{5}}+\dfrac{2}{3-\sqrt{10}}\)

Tính \(\sqrt{11-4\sqrt{7}}-\sqrt{2}\sqrt{8+3\sqrt{7}}\)

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Tính \(\sqrt{11-4\sqrt{7}-\sqrt{2}\sqrt{8+3\sqrt{7}}}\)