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Math Help - Polynomials

  1. #1
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    Polynomials

    a. Suppose that a market research company finds that at a price of p = $20, they would sell x = 62 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 = 72 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.

    This is what I have so far:
    First Point:
    (20, 62)

    Second Point:
    (10,72)

    Find the slope:
    m = (62-72)/(10-20) = -1

    What I need help on is:
    Find the equation of the line:

    p-p1=m(x-x1)





    Solve the equation in terms of p:
    p =
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  2. #2
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    Bzzzzt....

    Slope is bad. You MUST use the x-values and y-values in the same order. Your sign is wrong.
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  3. #3
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    Opps
    Thanks-is this correct?
    72-62/10-20= 10/-10= -1
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  4. #4
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    Quote Originally Posted by bball20 View Post
    Opps
    Thanks-is this correct?
    72-62/10-20= 10/-10= -1
    Pretty good, excepting the notation problems. Remember your order of operations. You should have written:

    (72-62)/(10-20)

    Notice how it is the same if you do it the other way.

    (62-72)/(20-10)

    As long as you are consistent.
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  5. #5
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    Thank you for your help.

    So I got this far, but I do not understand how to do the last part:



    p=62=-1(x-20)
    p=-1x+20 =62
    p=-x+82


    Now I need to solve the equation in terms of p:

    p=
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  6. #6
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    Quote Originally Posted by bball20 View Post
    p=62=-1(x-20)
    p=-1x+20 =62
    p=-x+82
    Not real sure what's going on here. Are these just typos?
    p-62=-1(x-20)
    p=-1x+20 +62

    Now I need to solve the equation in terms of p:

    p=
    This has me utterly baffled. You just did solve for 'p'. Why do you think you still need to solve for 'p'?
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