Question

$\sqrt{10 + \sqrt{90} }$
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Answer 1

$= = > \: \: \sqrt{10 + \sqrt{90} } \\ \\ = = > \: \: \sqrt{10 + \sqrt{10 \times 9} } \\ \\ = = > \: \: \sqrt{10 + 3 \sqrt{10} } \\ \\ = = > \: \: \sqrt{4 \sqrt{10} } \\ \\ = = > \: \: 2 \sqrt{\sqrt{10}}$