Đáp án:
$\begin{array}{l}
A = \left( {\sqrt {48} + \sqrt {15} + \sqrt {12} } \right).\sqrt 3 + 2\sqrt {{{\left( {4 - 2\sqrt 5 } \right)}^2}} \\
= 4\sqrt 3 .\sqrt 3 + \sqrt 5 .\sqrt 3 .\sqrt 3 + 2\sqrt 3 .\sqrt 3 + 2\left( {2\sqrt 5 - 4} \right)\\
= 12 + 3\sqrt 5 + 6 + 4\sqrt 5 - 8\\
= 10 + 7\sqrt 5
\end{array}$