`a)` `\sqrt{3+2\sqrt{2}}`
`=\sqrt{2+2\sqrt{2.1}+1}`
`=\sqrt{(\sqrt{2}+1)^2}`
`=|\sqrt{2}+1|`
`=\sqrt{2}+1` (do `\sqrt{2}+1>0)`
`b)` `\sqrt{8-2\sqrt{7}}`
`=\sqrt{7-2\sqrt{7.1}+1}`
`=\sqrt{(\sqrt{7}-1)^2}`
`=|\sqrt{7}-1|`
`=\sqrt{7}-1` (do `\sqrt{7}-1>0)`