Giúp mình câu b,i với ạ, vote 5 sao

Bài `18`:

`B) (sqrt{3} - 1) . sqrt{ 2sqrt{19 + 8sqrt{3}} - 4}`

` = (sqrt{3} - 1) . sqrt{ 2sqrt{16 + 8sqrt{3} + 3} - 4}`

` = (sqrt{3} - 1) . sqrt{ 2sqrt{(4 + sqrt{3})^2} - 4}`

` = (sqrt{3} - 1) . sqrt{ 2(4 + sqrt{3}) - 4}`

 ` = (sqrt{3} - 1) . sqrt{8 + 2sqrt{3} -4}`

` = (sqrt{3} - 1) . sqrt{3 + 2sqrt{3} + 1}`

` = (sqrt{3} - 1) . sqrt{ (sqrt{3} + 1)^2}`

` = (sqrt{3} - 1)(sqrt{3} + 1)`

` = 3 - 1`

` = 2`

`i) sqrt{302 - 20sqrt{6}} + sqrt{203 - 20sqrt{6}}`

` = sqrt{300 - 2 . 10sqrt{3} . sqrt{2} + 2} + sqrt{200 - 2 . 10sqrt{2} . sqrt{3} + 3}`

` = sqrt{ (10sqrt{3} - sqrt{2})^2} + sqrt{ (10sqrt{2} - sqrt{3})^2}`

` = 10sqrt{3} - sqrt{2} + 10sqrt{2} - sqrt{3}`

` = 9sqrt{3} + 9sqrt{2}`