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.

Question

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

Answer 1

a. X + 27.80*20 = 914
X = $358.

b. C = 358 + 27.80x
X = The number of years since 1981.

c. 2000-1981 = 19 years.
C = 358 + 17.80*19 = $528.20