# How do I graph a cost function like C(x) = 3x + 20,000?

##### 1 Answer
Jun 21, 2015

I think that your function can be used to model a service (say a health insurance) where you pay a fixed value (20,000) to join the program and 3 for each medical visit.

#### Explanation:

Your function is a linear function and is represented, graphically, by a straight line.

Considering an example you can immagine that it represents a medical insurance.

You pay $20,000 to join in and then you pay $3 for each visit: you can plot your function by using some values of $x$ and calculating the corresponding $C$:

For example:
$x = 0 , C \left(0\right) = 0 + 20 , 000 = 20 , 000$
$x = 1 , C \left(1\right) = 3 + 20 , 000 = 20 , 003$
$x = 2 , C \left(2\right) = 6 + 20 , 000 = 20 , 006$
...etc.

You can now plot these points on your graph.
So, graphically you have: