Answer:
Total cost 

Explanation:
Given: 
A cell phone plan costs`$200` to start.
Also, there is a `$50` charge each month.
To find: total cost (start up fee and monthly charge) to use the cell
Solution:
Start up fee = $200
Monthly charge = $50
Let 
 denotes number of months.
 denotes number of months.
Total cost (start up fee and monthly charge) to use the cell 
