pre calculus
posted by alexis .
1.)A utility company has the following rate schedule for natural gas usage in a city’s business district:
Monthly service charge: $8.80
Per therm service charge
1st 25 therms : $0.6686/therm
Over 25 therms: $0.85870/therm
(a) What is the charge for using 25 therms in one month?
(b) What is the charge for using 45 therms in one month?
(c) Construct a function that gives the monthly charge C for x therms of gas.
I am totally lost, can someone please show me how to do this???

is using x therms,
f(x) = 8.80 + .6686x for 0<=x<=25
25 therms cost $16.715, so
f(x) = 8.80+16.715 + .85870x
= 25.515 + .85870x for 25<x
now just plug in values for x, using the appropriate function 
what do you mean when you say, "the appropriate function?" what function are you referring to?

I mean to where I have to graph the following function using transformations. And have to be sure to graph all of the stages on 1 graph. Then I have to state the domain and range.

f(x) = 8.80+0.6686x for 0 < x <= 25
f(x) = 25.515+0.85870(25x) for x > 25