Question 271635
your point pairs are (x,y) = :


62,7000
63,7500
64,8000


the slope of the equation will be:


(8000 - 7000) / (64 - 62)


this becomes 1000 / 2 = 500


the equation will be y = 500 * x + b


take one of the points and replace x and y with it.


take the 63,7500 pair.


the slope intercept form of the equation becomes:


7500 = 500*63 + b which becomes:


7500 = 31500 + b


subtract 31500 from both sides of this equation to get:


b = -24000


that's the y-intercept of the equation which is the value of y when x = 0


your equation is:


y = 500x - 24000


a graph of your equation is shown below:


{{{graph (600,600,-10,100,-30000,30000,500x - 24000)}}}


a closer view of the graph to show the years of interest better is shown below:


{{{graph (1200,300,-10,70,-1000,10000,500x - 24000,7000,7500,8000)}}}


you can see that y = 7000 when x = 62 and y = 7500 when x - 63 and y = 8000 when x = 64.


the 3 horizontal lines are at y = 7000, 7500, 8000 respectively.