how to write a cost equation
4. We can use inequalities to compare the costs of two different products or services. A phone company has two different phone plans you can choose from. Find out how many calls must be made to make Plan A the better deal.
• Plan A: $45 a month for unlimited calling
• Plan B: $15 a month plus $0.10 per minute
Complete the following steps to solve the above problem:
a. Write the cost equation for Plan A:
b. Write the cost equation for Plan B:
c. Use the equations written in steps a) and b) to show the inequality that models the given conditions. Solve the inequality to find out how many calls must be made to make Plan A the better deal. Be sure to show all your steps to get full credit.
