- Identify the independent and dependent variables for the given linear situation. - Write an equation that represents the linear relationship between the variables. - Use the equation to answer the question. Be prepared to show how you used the function equation to answer the question. Situation: There is a linear relationship between the total cost of a gym membership for the month and the number of fitness class taken that month. One month Mari took 10 classes and it cost her $75. Another month she took 8 classes and paid $60. Question: If the total cost of a gym membership for the month was $97.50, how many fitness classes did Mari take? Answer: Mari attended fitness classes.