Question 584368
Let's say the function is
{{{E(t)=mt+b}}} and we want to find the numbers m abd b.
For the year 1992, t=0, because it is 0 years after 1992.
So {{{E(0)=m-0+b=b=70.7}}} gives us {{{highligth(b=70.7)}}}
For 1996, t=4, because 1996 is 4 years after 1992, and the life expectancy of males is
{{{E(4)=m*4+70.7=74.3}}}
That gives us the equation {{{4m+70.7=74.3}}}
{{{4m+70.7=74.3}}} --> {{{4m+70.7-70.7=74.3-70.7}}} --> {{{4m=3.6}}} --> 
{{{4m/4=3.6/4}}} --> {{{highlight(m=0.9)}}}
So the function is {{{highlight(E(t)=0.9t+70.7)}}}
For 2007, {{{t=2007-1992=15}}}. The life expectancy for males in 2007 can be predicted as
{{{E(15)=0.9*15+70.7=13.5+70.7}}} --> {{{highlight(E(15)=84.2)}}}