Question 1007875
(x+6)/(3x-27) 
Yes, only the values in the denominator need be considered.
Thus when 3x - 27 = 0, we have a disallowed value of x...
3x - 27 = 0
3x = 27
x = 9
In interval notation, we can write
(-inf, 9) or (9, inf)
as the allowable values.