Ta có :
$\sqrt[]{5+2\sqrt[]{6}} - \sqrt[]{(\sqrt[]{3}+\sqrt[]{2})^2} $
$=\sqrt[]{(\sqrt[]{3})^2+2.\sqrt[]{3}.\sqrt[]{2}+(\sqrt[]{2})^2} - \sqrt[]{(\sqrt[]{3}+\sqrt[]{2})^2} $
$ = \sqrt[]{(\sqrt[]{3}+\sqrt[]{2})^2} -\sqrt[]{(\sqrt[]{3}+\sqrt[]{2})^2} $
$ = 0 $