Suppose a market research company finds that at a price of p = $20, they would sell x = 42 tiles each month. If they lower the price to p = $10, then more people would purchase the tile, and they can expect to sell x = 52 tiles in a month’s time. Find the equation of the line for the demand equation. Write your answer in the form p = mx + b. Hint: Write an equation using two points in the form (x,p).

(42,20),(52,10) are two points.

The standard two point form is y-y1=m(x-x1) and m=(y2-y1)/(x2-x1).

p-20=(10-20)/(52-42)*(x-42).

p-20 =-1(x-42).

p-20=-x+42.

p=-x+42+20

p= -x+62.