For this case, the first thing we must do is define a variable.
We have then:
m: number of months.
We write the expression that models the problem:
f (m) = 40m + 35
Then, for 10 months we have:
m = 10
Substituting values:
f (10) = 40 (10) + 35\\f (10) = 400 + 35\\f (10) = 435
an expression for the total cost for m months is:
f (m) = 40m + 35
for 10 months of service:
f (10) = 435
