math
posted by Anonymous .
media service charges $30 for a phone and $20 month for its economy plan. find a model that determines the total cost,C(t) of operating a media services phone for 1 months
C(t)=
use the model to find the total cost for 3 months of service
total cost=

I'm using 'x' instead of '+' to make the answer less confusing.
The cost for the phone is $30, and that's a one time charge.
The cost for x months would be 20 times x, or 20x
So, the model for the total cost is C(x) = 30 + 20x.
x= 30 + 20(1)= 50
x= 30 + 20(3)= 90
If x = 1 month, the cost would be $50. For three months, it would be $90, and so forth.