Question 1033764
c(x) = 25x + 80000.


your x value has to be less than or equal to 20000.
presumably it also has to be greater than 0, because you can't have a negative number of units produced.


so your domain is 0 <= x <= 20,000.


when x is equal to 0, your total cost is 80,000.


when x is equal to 20,000, your total cost is 25 * 20,000 + 80,000 = 580,000.


your range is 80,000 <= y <= 580,000.


the graph of your cost equation is y = 25*x + 80000


you restrictions are that:


x can't be less than 0.
y can't be less than 0.
x can't be greater than 20,000.


based on those restrictions, your graph would look something like this.


<img src = "http://theo.x10hosting.com/2016/051001.jpg" alt="$$$" </>


the shaded regions are the value that x and y can't take.


y can't be less than 0.
x can't be less than 0 or greater than 20,000.


the permisible values for your cost function are in the white and on the line of y = 25*x + 80,000.


the limits are between 80,000 and 580,000.