Question 1037782
The description gives two points on a line, (x,y) for Demand for y and Price for x, if you want those ways to assign the quantities.  These would be the points  (40,1000) and (20,2000).  Find the line which fits the form  y=mx+b.


{{{y-mx=b}}}
{{{b=y-mx}}}
Pick either point.
{{{b=1000-((2000-1000)/(20-40))40}}}
{{{b=1000-(1000/(-20))*40}}}
{{{b=1000+(100/2)*40}}}
{{{b=1000+50*40}}}
{{{b=1000+2000}}}
{{{b=3000}}}
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Look into one of the steps to see m=-50.
{{{highlight(y=-50x+3000)}}}


That is not the only way to solve the example.  I used only slope-intercept form, but the point-slope form can be used instead and later adjusted to slope-intercept form.  Which way to assign the variables and what "names" for variables you use can be changed.  I chose x and y and assigned as done.  This was DEMAND as a function of unit price.