Answer: 1) The y-intercept seems to mean that if the price is 0, there would be 225 "sold" (given away). As the price increases, the number sold decreases.
2.) It is a function. For each x-value, price, there is a unique y-value. This graph passes the "vertical line test."
3.) The slope could be positive if "perceived value" correlates with the price of the item. People may be willing to buy more if they believe that the higher price means higher quality, better performance, longer lasting, etc.
Explanation:
The equation of this graph is y= -25x +225
where the x represents the price and y represents the number sold.
For every unit increase in price, 25 fewer items are sold.
Regarding question 3: The slope might not be as steep, but it could be positive when people are attracted to brand names with reputations for higher quality, or simply because they trust the brand name and are willing to pay more. Or the packaging and advertising are more attractive!