Respuesta :
You cannot have negative number under square root, so
6-x>=0 then x<= 6
And
3x-9>=0 then x>=3
Therefore the range is:
3<=x<=6
Or
[3,6]
6-x>=0 then x<= 6
And
3x-9>=0 then x>=3
Therefore the range is:
3<=x<=6
Or
[3,6]