The total charges for the first club as a function of the number of rentals (x) are
... f1 = 25 + 2.50x
The total charges for the second club are
... f2 = 3.25x
We want to find x so that f1 < f2.
... f1 < f2
... 25 + 2.50x < 3.25x
.. 25 < 0.75x . . . . . . . . . . subtract 2.50x
... 25/0.75 < x . . . . . . . . . divide by the coefficient of x
... 33 1/3 < x
You must rent 34 videos or more to make the first club more economical.
