Question

What is the domain and range of `f(x)=7`?

Answer 1

Domain - all real numbers.
Range - only one number `y=7`.

Explanation:

This is a function defined for all real arguments `x`, so its domain is all real numbers `(-oo,+oo)`.

Since for any value of an argument the function takes a value of `7`, its range is one and only one real number `y=7`.