Answer
The graph of the function C(x) as a funtion of x:
Work Step by Step
Basic monthly charge $\$$35
Number of free minutes = 400
Charges for each additional minute of usage = 10 cents
The monthly cost in dollars is represented by C
The total number of calls is x
The cost function is
$C(x)= 35 \ for \ x \leq 400$
$C(x)=35+ \frac{1}{10} (x-400) \ for \ x \gt 400$
