Question 143894
E(t)=at+b , we have to find a and b (real numbers)
In 1991, the life expectancy of males in a certain country was 68.5 years.
t represent the number of years since 1991.
then E(0)=68.5 then b=68.5
then
E(t)=at+68.5
Using now:In 1996 it was 71.1 years
E(5)=a5+68.5=71.1 then 5a=2.6 then a=0.52

then E(t)=0.52t+68.5