the annual household cost of telephone service in the US increased at a relatively constant rate of $27.80 per year from 1981 to 2001. in 2001 the annual household cost of telephone service was $914.
a: what was the annual household cost of telephone service in 1981?
b: write an equation that gives the annual household cost of telephone service as a function of the number of years since 1981.
c: find the household cost of telephone service 2000