Question

What is the domain of f(x) = 5x

Answer 1

Answer:

(-infinity, +infinity)

Step-by-step explanation:

Even tho' f(x) = 5x has only one term, it's still classified as a polynomial.  All polynomials are defined on all x:  (-infinity, +infinity).

Answer 2

Any real number multiplied by -5 and to which 4 is then added will give a real answer, So the function is defined for all real values of x.