4Ta có$:(\sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}})^2=20-2\sqrt{(10-6\sqrt{2})(10+6\sqrt{2})}=20-2\sqrt{100-72}=20-4\sqrt{7}$$\Rightarrow \sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}}=-\sqrt{20-4\sqrt{7}}$Ta có:$H=-\frac{\sqrt{4(5-\sqrt{7})}}{5-\sqrt{7}}-\sqrt{2^2-2.2.\sqrt{5}+(\sqrt{5})^2}=-\sqrt{4}-\sqrt{(\sqrt{5}-2)^2}=-2-\sqrt{5}+2=-\sqrt{5}$
4Ta có$:(\sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}})^2=20-2\sqrt{(10-6\sqrt{2})(10+6\sqrt{2})}=20-2\sqrt{100-72}=20-4\sqrt{7}$$\Rightarrow \sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}}=\sqrt{20-4\sqrt{7}}$Ta có:$H=\frac{\sqrt{4(5-\sqrt{7})}}{5-\sqrt{7}}-\sqrt{2^2-2.2.\sqrt{5}+(\sqrt{5})^2}=\sqrt{4}-\sqrt{(\sqrt{5}-2)^2}=2-\sqrt{5}+2=4-\sqrt{5}$
4Ta có$:(\sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}})^2=20-2\sqrt{(10-6\sqrt{2})(10+6\sqrt{2})}=20-2\sqrt{100-72}=20-4\sqrt{7}$$\Rightarrow \sqrt{10-6\sqrt{2}}-\sqrt{10+6\sqrt{2}}=
-\sqrt{20-4\sqrt{7}}$Ta có:$H=
-\frac{\sqrt{4(5-\sqrt{7})}}{5-\sqrt{7}}-\sqrt{2^2-2.2.\sqrt{5}+(\sqrt{5})^2}=
-\sqrt{4}-\sqrt{(\sqrt{5}-2)^2}=
-2-\sqrt{5}+2=-\sqrt{5}$