The three data points (1990, $0.35), (1995, $1.40), (2000, $2.45) give the average cost of an ice cream cone for each of the years shown. The three points lie on a line. What is the equation of the line?

I know the difference between each costs is $1.05. I am clueless about how to make this info into an equation.

Question

The three data points (1990, $0.35), (1995, $1.40), (2000, $2.45) give the average cost of an ice cream cone for each of the years shown. The three points lie on a line. What is the equation of the line?

I know the difference between each costs is $1.05. I am clueless about how to make this info into an equation.

anonymous · Answer

Okay so you know that these 3 points can be made into a slope correct?

anonymous · Answer

and from there that is why they want you to find the average cost, so that over time, you can find the average change

anonymous · Answer

giving the rise/run

anonymous · Answer

To do that I take the difference of greatest and least and divide by the amount of year?

anonymous · Answer

not really, you must add the values of all three costs (.35+1.40+2.45) and then divide it by the amount of years

anonymous · Answer

so it would be .42 average

anonymous · Answer

ok,  i got that. so...y=.42x + .35?

anonymous · Answer

yes i believe that would be the answer

anonymous · Answer

okay, thanks so much!