In 1993, the life expectancy of males in a certain country was 72.7 years. In 1997, it was 76.3 years. Let E represent the life expectency in yeart and let t represent the numbers of years since 1993.

The linear function E(t) that fits the data is

E(t)= t+ round to the nearest tenth

Use the function to predict the life expectancy of males in 2006

E(13)=

Solution:

     m = slope = (76.3 - 72.7)/(1997- 1993) = 1

     E(t) = mt + b = t + b

           = t + 72.7

    E(13) = 13 + 72.7 = 85.7