68 is composite it has more factors than 1 and itself
Answer:

Step-by-step explanation:
Fixed monthly fee = $20
Amount charged per minute for long distance calls = $0.20
denotes total cost such that
minutes are used for long distance calls.
Amount charged for
minutes for long distance calls 
Therefore, an equation for the total cost, C, when N minutes are used for long distance calls is 
The goal to proving identities is to transform one side into the other. We can only pick one side to transform while the other side stays the same the entire time. The general rule of thumb is to transform the more complicated side (though there may be exceptions to this guideline).
So I'll take the left hand side and try to turn it into 
One way we can do that is through the following steps:

Since we've shown that the left hand side transforms into the right hand side, this verifies the equation is an identity.
Answer:
15.874507866388
Step-by-step explanation: