F(x) = 2x + 8 Find the DOMAIN?

A function is any process that gives one output value for each qualified input value. For instance, a square root is not a function because each input gives two outputs. Qualified inputs are called "domain" and possible outputs are called "range".

F(x) = 2x + 8 By inspection, we see that this is a function and valid inputs, domain, are all real numbers. Imaginary numbers are disqualified because of the square root involved. Possible outputs, range, are all real numbers.