SOLUTION: I am completely lost on this problem can you please explain? A sales person observes that if an item is priced at $6 per item then 4 items are sold. If it is priced at $8 per it

Question 126141: I am completely lost on this problem can you please explain?
A sales person observes that if an item is priced at $6 per item then 4 items are sold. If it is priced at $8 per item, 2 items are sold. Find an equation to model the number y of items sold for x dollars per item.
Answer by marcsam823(57) (Show Source): You can put this solution on YOUR website!
The primary goal of this problem is to find the equation of a line. This is expressed as y = mx + b, where m is the slope of the line and b is the y-intercept (where the line crosses the y axis).
If we remove the "disguises" of dollars and number of items we are simply left with two x-coordinates and two y-coordinates as shown in the chart below:
x | y
_____
6 | 4
8 | 2
1. To find the slope of this line:
m = = = = -1
Using y = mx + b:
y = -1x + b
2. Substitute for x and y (plug in either of the two points - we'll use (6,4)):
y = mx + b
4 = -1(6) + b
3. Find the y-intercept by solving for b:
4 = -6 + b
b = 10
The equation is:
y = -x + 10
Check:
Point (6,4)
4 = -(6) + 10
4 = 4
Point (8,2)
2 = -(8) + 10
2 = 2

RELATED QUESTIONS
Hi. I am completely lost about this problem. Can you please explain how you get the... (answered by drk,jsmallt9)

Question--Leo Held a Garage Sale. He Priced All The Item For Either a Dime or a Quarter.... (answered by ankor@dixie-net.com)

Factor the following polynomial completely 14x^2 - 20x + 6 Can you explain the... (answered by jim_thompson5910)

An item is priced at $14.33. If the sales tax is 5%, what does the item cost including... (answered by rfer)

An item is priced at $14.67. If the sales tax is 5%, what does the item cost including... (answered by josmiceli)

An item is priced at $13.43. If the sales tax is 8%, what does the item cost including... (answered by ikleyn)

Solve the inequality (3x-2)/(x+4) <_ 0 if you could please thoroughly explain it... (answered by josgarithmetic)

Solve the inequality ((2x+5)(x-1)^2)/(x+2)^3 _> 0 if you could please thoroughly... (answered by greenestamps)

Can you please explain how this problem is solved in detailed steps? My directions say... (answered by jim_thompson5910)