CCGPS AA 6.3.1 Example 3

Ann is trying to decide whether to sign up for a new “pay as you go” cell phone plan. The plan charges $0.25 per minute for calls and $0.10 per text message, which includes all taxes and fees. She wants to spend no more than $100 monthly for cell service. Write the constraint equation and then graph the solution. Finally, determine the domain of the graph (minutes for calls) and interpret how it relates to this situation.
  1. Write a constraint equation for the relationship described.
  2. Rewrite the equation in slope-intercept form, , to determine the slope and -intercept.
  3. Graph the result by hand or using a graphing calculator.
  4. Determine the domain of the graph and how it relates to this situation.
This applet is provided by Walch Education as supplemental material for the CCGPS Advanced Algebra program. Visit for more information on our resources.