SOLUTION: Please Help! I am new to this page I have been working on this question for a while and I can not figure it out. In 1993, the life expectancy of males in a certain country was

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Please Help! I am new to this page I have been working on this question for a while and I can not figure it out. In 1993, the life expectancy of males in a certain country was      Log On


   



Question 1083313: Please Help! I am new to this page I have been working on this question for a while and I can not figure it out.
In 1993, the life expectancy of males in a certain country was 73.6 years. In 1998​, it was 77.2 years. Let E represent the life expectancy in year t and let t represent the number of years since 1993

Found 2 solutions by MathLover1, josgarithmetic:
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

In 1993, the "life expectancy of males in a certain country" was 73.6 years.
so, E=73.6 years and t=1993
In 1998​, it was 77.2 years, so
E=77.2 years and t=1998

The linear function E%28t%29 that fits the data is:
E%28t%29=at+%2B+b................use E=73.6 years and t=1993
73.6=a%2A1993+%2B+b....solve for b
b=73.6-a%2A1993.........eq.1

E%28t%29=at+%2B+b................use E=77.2 years and t=1998
77.2=a%2A1998+%2B+b....solve for b
b=77.2-a%2A1998.........eq.2

from eq.1 and eq.2 we have

73.6-a%2A1993=+77.2-a%2A1998
73.6-77.2=a%2A1993-a%2A1998
-3.6=a%281993-1998%29
-3.6=a%28-5%29
a=-3.6%2F%28-5%29
a=+0.72
now find b
b=73.6-a%2A1993.........eq.1
b=73.6-0.72%2A1993
b=73.6-1434.96
b=-1361.36
then, equation is:
E%28t%29=at+%2B+b...if a=+0.72 and b=-1361.36
E%28t%29=0.72t+-1361.36


Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Linear data pair as (t, E).
Two particular points are (0, 73.6) and (5, 77.2).


For making a linear equation fit,
E=%28%2877.2-73.6%29%2F%285-0%29%29t%2B73.6, in slope-intercept form since one of your points is already the vertical axis intercept.

Simplify the slope:
E=%283.6%2F5%29t%2B73.6
OR better,
highlight%28E=%2818%2F25%29t%2B73.6%29