SOLUTION: In 1990, the life expectancy of males in a certain country was 66.3 years. In 1997, it was 70.0 years. Let E represent the life expectancy in years t and let t represent the numb

Algebra ->  Equations -> SOLUTION: In 1990, the life expectancy of males in a certain country was 66.3 years. In 1997, it was 70.0 years. Let E represent the life expectancy in years t and let t represent the numb      Log On


   

Question 230356: In 1990, the life expectancy of males in a certain country was 66.3 years. In 1997, it was 70.0 years. Let E represent the life expectancy in years t and let t represent the number of years since 1990. E(t)= ___t +____ round to the nearest tenth. Use the fuction to predict life expectancy of males in 2009. E (19) =______ round to the nearest tenth. I'm sorry I tried and I can not get this problem
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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In 1990, the life expectancy of males in a certain country was 66.3 years.
In 1997, it was 70.0 years.
Let E represent the life expectancy in years t and let t represent the number
of years since 1990. E(t)= ___t +____ round to the nearest tenth.
Use the function to predict life expectancy of males in 2009
:
:
Find the slope
In 1990; x1=0 and y1=66.3
In 1997; x2=7 and y2=70
:
Find the slope (m) using the slope equation: m = %28y2-y1%29%2F%28x2-x1%29
m = %2870-66.3%29%2F%287+-+0%29%29 = %283.7%29%2F%287%29 = .53
:
Use the point/slope formula to write the equation; y - y1 = m(x - x1)
y - 66.3 = .53(x - 0)
y = .53x + 66.3
:
therefore:
The Linear function E(t) that fits the data is.
E(t)= .53t + 66.3
:
Use the Function to predict the life expectancy of males in 2009.
This means t=19; substitute 19 for t in the equation
E(19)= .53(19) + 66.3
E(19)= 10 + 66.3
E(19)= 76.3 yrs is the life expectancy in 2009