What is the domain of #f(x) = 6/(4-x)#?

1 Answer
Jan 24, 2017

#RR-{4}#

Explanation:

Here we have

#f(x)=6/(4-x)#

Consider

#f(4)=6/(4-4)=6/0# which is undefined because you can't divide by zero.

Because of this #x# cannot take the value #4#. Since this function is defined for the rest of the Real numbers #RR#; we have that the domain of #f# is #RR-{4}# or the set of Real numbers not including four.