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 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 = {{{(y2-y1)/(x2-x1)}}}
m = {{{(70-66.3)/(7 - 0))}}} = {{{(3.7)/(7)}}} = .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