Question

What is the domain and range of `y = x + 3`?

Answer 1

`domf=RR`
`ranf=RR`

Explanation:

`f(x)=x+3`

Domain

Is there any value of `x` that will make `f(x)` undefined?

The answer to this is no, so the domain is the set of all real numbers `RR`.

`domf=RR`

Range

You will notice that the graph of `x+3` is just a line, meaning it will intersect all values of `y` (since it increases and decreases without limit).

Therefore, the range is also the set of all real numbers `RR`.

`ranf=RR`

Just keep this in mind. When you're given a linear function, its domain and range are both the set of all real numbers (unless the problem tells you it isn't).