Description: Use a graph with two, plotted points to express an equation. In the graph and table above, d is the total number of dollars that you pay for your gym membership, so that's d right over there, and t is the time in months that you keep the membership. Write an equation for the amount of money d that you pay for your gym membership, if you keep the membership for t months. So if I were to write this as an equation, the dependent variable here is the amount that I pay in dollars.*Teacher Advisor is 100% free.