Question

What is the domain and range of `y=2x+3`?

Answer 1

Domain is `x epsilon RR`
Range is `y epsilon RR`

Explanation:

There are no limitations placed on possible values of `x` [the Domain] (for example, no value of `x` would cause an attempt to divide by zero)
so `x` can take on any value. (for the purposes of this question I've assumed that you are working with Real numbers, `RR`, but `x` could in fact be any complex , `CC`, value.

We can see that any value within `RR` (or `CC`) could be generated for `y` (the Range) by noting that the inverse of the function:
`x= (y-3)/2` places no limitations on the value of `y`