Question

What are the domain and range of f(x) = 4x – 8?

Answer 1

Answer:

Since this function is definable for all real values of x,

Domain(f(x)) = R = (-∞,∞)

Now,

Let 4x-8=y

4x = y+8

x = (y+8)/4

Since x is definable for all real values of y,

Range(f(x)) = R = (-∞,∞)

Answer 2

A) domain: {x | x is a real number}; range: {y | y > –8}