Question

Please help me!!! I don't understand how to solve it(((

Answer 1

$\sqrt{( \sqrt{7-2 \sqrt{10} }+ \sqrt{2} )*2 \sqrt{5} }= \\ = \sqrt{( \sqrt{2-2 \sqrt{2*5}+5 }+ \sqrt{2} )*2 \sqrt{5} }= \\ \sqrt{( \sqrt{( \sqrt{2}- \sqrt{5})^{2} }+ \sqrt{2} )*2 \sqrt{5} }= \\ \sqrt{( \sqrt{5}- \sqrt{2} + \sqrt{2} )*2 \sqrt{5} }= \\ \sqrt{ \sqrt{5} *2 \sqrt{5} }= \\ \sqrt{2*5} = \sqrt{10}$
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