Thread: 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 =

Bzzzzt....

Slope is bad. You MUST use the x-values and y-values in the same order. Your sign is wrong.

Opps
Thanks-is this correct?
72-62/10-20= 10/-10= -1

Originally Posted by bball20

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.

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=

Originally Posted by bball20

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'?