Question 395426
<font color=blue>What is (f + g)(3)?  I get 23.</font>


You are correct. Good job.



<font color=blue>What is the domain of (f + g)(x)?  Is is 3 or 23? </font> Both and more (see why below)



Note: I'm assuming you meant (f + g)(x) and NOT (f + g)(3)



Remember what the domain is: the domain is the set of all possible inputs. Since 3 and 23 work for inputs, they are clearly part of the domain. But are these the only values of x that work? The answer is no. There are definitely a lot more. For example, inputs like x=0, x=5, and x=21 all work too.



It turns out that ANY real number works as an input for (f+g)(x). So this means that the domain is the set of all real numbers.



If you need more help, email me at <a href="mailto:jim_thompson5910@hotmail.com?Subject=Algebra%20Help">jim_thompson5910@hotmail.com</a>


Also, feel free to check out my <a href="http://www.freewebs.com/jimthompson5910/home.html">tutoring website</a>


Jim