1)
`\sqrt{4-2\sqrt3}`
`=\sqrt{3-2\sqrt3+1}`
`=\sqrt{(\sqrt3-1)^2}`
`=|\sqrt3-1|`
`=\sqrt3-1` (Vì `\sqrt3>1`)
4)
`\sqrt{5-2\sqrt6}`
`=\sqrt{3-2\sqrt6+2}`
`=\sqrt{(\sqrt3-\sqrt2)}`
`=|sqrt3-\sqrt2|`
`=\sqrt3-\sqrt2` (Vì `\sqrt3>\sqrt2`)
Câu 2,3 bn xem lại đề :V