Question

How do you find the domain of `f (x) = -1 / ( x + 3)`?

Answer 1

The domain of a function is a set of all x, for which the function exists or `f` be defined

Explanation:

In our case, the only value for `f(x)` does'nt exist is `-3`

En efect: if `x=-3` then `f(-3)=-1/(-3+3)=-1/0`. There is no number which multiplied by 0 gives -1

For this reason the domain is `dom(f(x))={x in RR // x!=-3}`