[tex]a)\\\\ \sqrt{(2- \sqrt{5})^2}+ \sqrt{(7-3 \sqrt{5})^2 }=| 2- \sqrt{5} |+|7-3\sqrt{5}|= \sqrt{5}-2+7-3\sqrt{5} =\\\\= 5-2\sqrt{5}\\\\b)\\\\\sqrt{ (2 \sqrt{2}-3 )^2}+\sqrt{ (3\sqrt{ 2} - 4)^2 }= | 2 \sqrt{2}-3 |+ |3\sqrt{ 2} - 4|= 3- 2 \sqrt{2} + 3\sqrt{ 2} - 4 =\\\\= \sqrt{2}- 1[/tex]
