Sample Problem

In order to become a member at a local gym, there is a $50 startup fee, then a $20 fee every month. Write an equation in slope-intercept form modeling this situation where c, the total cost, is a function of g, the number of months spent at the gym.

c = g +


No matter how many months you spend at the gym, if you want to become a member, it will cost $50. This can be thought of as the y-intercept, or b value.

After this, the total cost increases by $20 each month, so this can be thought of as the slope.

The equation for this situation is therefore c = 20g + 50.