SOLUTION: (Can someone please help me with this question?) In 1992, the life expectancy of males in a certain country was 71.1 years. In 1997, it was 73.4 years. Let E represent the life ex

Algebra ->  Linear-equations -> SOLUTION: (Can someone please help me with this question?) In 1992, the life expectancy of males in a certain country was 71.1 years. In 1997, it was 73.4 years. Let E represent the life ex      Log On


   



Question 841582: (Can someone please help me with this question?)
In 1992, the life expectancy of males in a certain country was 71.1 years. In 1997, it was 73.4 years. Let E represent the life expectancy in year t and let t represent the number of years since 1992.
The linear function E(t) that fits the data is E(t)=___?t+__?(Round to the nearest tenth)
Use the function to also predict the life expectancy of males in 2003.
E(11)=___?(Round to the nearest tenth)

Found 2 solutions by ewatrrr, josmiceli:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
E(t)=___?t+__? | y+=+mx+%2Bb
find slope:
(1997,73.4)
(1992, 71.1) m = %2873.4-71.1%29%2F%281997-1992%29 = 2.3/5 = .46
Use 2nd point to find 'b' where t = 0
E(t)= .46t+ 71.1
E(11) = .46(11) + 71.1

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
What they want you to do is find the slope of
a straight line that passes through the points
( 71.1, 0 ) and ( 73.4, 5 )
-----------------------
+E%28t%29+ is plotted on the vertical axis
+t+ is plotted on the horizontal axis
I call the year 1992 +t+=+0+
Then 1997 becomes ++t+=+5+ ( 5 years later )
------------------------------------------
Use the general point-slope formula
+%28+E+-+71.1+%29+%2F+%28+t+-+0+%29+=+%28+73.4+-+71.1+%29+%2F+%28+5+-+0+%29+
+%28+E+-+71.1+%29+%2F+t+=+%28+73.4+-+71.1+%29+%2F+5+
Multiply both sides by +5t+
+5%2A%28+E+-+71.1+%29+=+t%2A%28+73.4+-+71.1+%29+
+5E+-+355.5++=+2.3t+
+5E+=+2.3t+%2B+355.5+
+E+=+.46t+%2B+71.1+
-----------------------
Check the answer:
( 73.4, 5 )
+E+=+.46t+%2B+71.1+
+73.4+=+.46%2A5+%2B+71.1+
+73.4+=+2.3+%2B+71.1+
+73.4+=+73.4+
OK
-----------------------
2003 - 1992 = 11 years
+t+=+11+
+E+=+.46t+%2B+71.1+
+E+=+.46%2A11+%2B+71.1+
+E+=+5.06+%2B+71.1+
+E+=+76.16+
----------------------
+E%2811%29+=+76.16+ also
----------------------
Here's a plot of the line:
+graph%28+400%2C+400%2C+-2%2C+15%2C+-10%2C+100%2C+.46x+%2B+71.1+%29+