linear equation

[wolfpetal]

In 2007, the life expectancy for a female born in the US was 80.97 years and was increasing at a rate of 0.3 years per year. Assume that this rate on increase remained constant.

a. Model this situatin by a linear equation
b. Use the equation in part (a) to estimate the life expectancy of a female born in the US in 2020.


The year 2007 is year 0

I was thinking I should use 0=mx+b is this correct?
I think m should be 0.3 and b should be 80.97

Therefore the equations should be
0=0.3x + 80.97

 

[wjm11]

In 2007, the life expectancy for a female born in the US was 80.97 years and was increasing at a rate of 0.3 years per year. Assume that this rate on increase remained constant.

a. Model this situatin by a linear equation
b. Use the equation in part (a) to estimate the life expectancy of a female born in the US in 2020.


The year 2007 is year 0

I was thinking I should use 0=mx+b is this correct?
I think m should be 0.3 and b should be 80.97

Therefore the equations should be
0=0.3x + 80.97

Pretty close, but not quite right. Life expectancy depends on the year born, so life expectancy is the dependent variable (and is on the y axis), and the year born is the independent variable (and is on the x axis). So, it's not "0 = mx + b", but rather y (life expectancy) = mx + b. Therefore, your final equation is

y = 0.3x + 80.97