`B= (sqrtx +2)/(sqrtx-2)`

`A/B >= 2/(x+2)`

`<=> 2/(sqrtx-2) :  (sqrtx +2)/(sqrtx-2) >= 2/(x+2)`

`<=> 2/(sqrtx-2) .  (sqrtx -2)/(sqrtx+2) >= 2/(x+2)`

`<=> 2/(sqrtx+2) >= 2/(x+2)`

`<=>sqrtx +2 <= x+2`

`<=>x-sqrtx >= 0`

`<=>sqrtx(sqrtx -1)>=0`

`<=>sqrtx-1>=0(text(vì) sqrtx >= 0)`

`<=>sqrtx >=1`

`<=>x>=1`

Kết hợp với điều kiện `=>x >= 1 ; x ne 4`