<PRE><B>Question 146890</B>
a. Suppose that 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)).
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Points: (42,20) and (52,10)
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slope = (10-20)/(52-42) = -10/10 = -1
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p = mx+b where m = -1 and p=20 when x=42; solve for &quot;b&quot;:
20 = -1*42 + b
b = 62
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EQUATION:
p = -x + 42
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Cheers,
Stan H. 
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