my answer is diffrent then the book. its a 2 part question. a. write an equation describing the relationship between year and persons per square mile. use orded pairs of the form (years past 2006, persons per square mile) b. use this equation to predict the persons per square mile population in 2020. the equation i come up with is y=3/5x-5593/5 the book says its y=3/5x-85. what am I doing wrong? the given points are (2006,85) (2011,88)
+129840 I think the problem is "the years past 2006"....if we use 2006 as "year 0," then 2011 will be "year 5" .....and we have the points (0,85) (5,88) ....the slope is given by :
[ 88 - 85 ] / [5 -0] = 3/5
And using either point - I'll use the first one - the equation becomes
y - 85 = (3/5) (x - 0 )
y = (3/5)x + 85
This equation is correct....note that putting in "5" for x gives us 88
So.... in 2020, x will = 14 and we have
y = (3/5)(14) + 85 = 93.4 persons per square mile
