Question

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

Answer 1

`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.