I'm pretty sure that by the time you reach this problem, you've learned to find

the equation of a line that passes through two given points. You have two points: (2, 100) and (5, 205). The equation of the line through them is [ y = 35x + 30 ].

6). The initial membership fee ... the cost for walking in the door and signing up,

before any months, is $30. (Also the y-intercept.)

7). The cost per month is $35. (The slope of the line.)

8). We already did that, up above. [ y = 35x + 30 ].

9). 'x' in the equation is the number of months.

There are 12 months in one year.

y = 35(12) + 30 = $450