√(3-√5) - (√3 + √5)= √3 - √5 -√3 - √5 = -2√5
1: \(=\dfrac{1}{\sqrt{2}}\cdot\left(\sqrt{6-2\sqrt{5}}-\sqrt{6+2\sqrt{5}}\right)\)
\(=\dfrac{1}{\sqrt{2}}\left(\sqrt{5}-1-\sqrt{5}-1\right)=-\sqrt{2}\)
2: =>3 căn x=6
=>x=4
3: =>|x+2|=3
=>x+2=3 hoặc x+2=-3
=>x=-5 hoặc x=1