How can you model data with a linear function? You must provide a real-world example and show how to model the problem using a linear function. Be sure to explain how you know it is a function.

Question

This is a discussion question I need help on, can somebody please help me understand how and where to begin? Thanks

Answer 1

I just paid $11.04 for 12 litres of gas, while last week I paid $$59.80 for 65 litres of gas at the same price.
If L is the number of litres, and C is the cost in dollars per L, find the equation for the cost in terms of L

So you have 2 points of the form (L,C) and they are (12, 11.04) and (65, 59.80)

step 1:
find the slope :
slope = (59.8-11.04)/(65-12) = .92

since we know that for 0 L of gas , I would pay $0.00, the relations is a direct variation and it is
C = .92L

Remember a linear function is graphed by a straight line.
Pick different values of L, then find C
Plot those points, showing a straight line

Answer 2

Okay, thank you Reiny!:)

Answer 3

Wait... isn't a function supposed to go like: y = f(x) or something? Where does that come in to play here?

Answer 4

Do you like
C(L) = .92L better?

so the horizontal axis will be labeled L
and the vertical axis as C(L)