SOLUTION: in 1992, life expectancy of males in a certain country was 65.1 years. in 1996, it was 68.9, let E represent the life expectancy in year t and let r represent the number of years s

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Question 459056: in 1992, life expectancy of males in a certain country was 65.1 years. in 1996, it was 68.9, let E represent the life expectancy in year t and let r represent the number of years since 1992. the linear function E(t) that fits the data is
E(t)=_t+_
use the function to predict the life expectancy in 2006
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The years gets plotted on the horizontal axis
The Life expectancy is plotted on the vertical axis
First find the slope, m, of the line
It is ( change in y ) / ( change in x )
+m+=+%28+69.9+-+65.1+%29+%2F+4+ (note that 4 = 1996 - 1992)
+m+=+4.8+%2F+4+
+m+=+1.2+
Now use the general formula for a line:
+y+=+mx+%2B+b+, but in this case:
+E%28t%29+=+m%2At+%2B+b+ where b is the vertical intercept ( where t=0)
+E%28t%29+=+1.2%2A0+%2B+b+
You are given:
When +t=0+, or in 1992, +E%280%29+=+65.1+, so
+65.1+=+1.2%2A0+%2B+b+
++b+=+65.1+
So the whole equation is:
+E%28t%29++=+1.2t+%2B+65.1+
Then they ask you for +E%284%29+ ( 1996 )
+E%284%29+=+1.2%2A4+%2B+65.1+
+E%284%29+=+4.8+%2B+65.1+
+E%284%29+=+69.9+
The life expectance is 69.9 years in 1996