f(x) = 4x - 8
The domain of a function is the set of all the x-values of the function
and the range is the set of all the y-values of the function.
Since we can plug in any real number into the equation for x,
positive or negative, our domain will be the set of all real numbers.
So the domain is R.
Now I like to plug in a few values for x.
A good place to start is when x = 0.
f(0) = 4(0) - 8.
When we evaluate f(-1), we get -12.
When we evaluate f(1), we get -4.
Let's test one more to see if we can get a positive result.
Let's evaluate f(22).
This gives us 4(22) - 8 or 88 - 8 which is 80.
Since there are no restrictions on x, the range is R.