Suppose that in 2001, the average cost of a gallon of milk was $1.89. In 2007 the average price was $4.41.

Assuming the relationship is linear, find the equation of the line that models the price of milk over time.

Question

Suppose that in 2001, the average cost of a gallon of milk was $1.89.  In 2007 the average price was $4.41. 

Assuming the relationship is linear, find the equation of the line that models the price of milk over time.

mertsj · Answer

At time 0 which is 2001, the cost was 1.89  That gives us the ordered pair, (0,1.89)
At time 6 which is 2007, the cost was 4.41.  That gives us the ordered pair, (6,4.41)
So now that we have two ordered pairs, we can find the slope of the line and then write its equation. using point slope form.

anonymous · Answer

So it would be y= ax + b or is it y2 - y1 over x2- x1

mertsj · Answer

To find the slope it's the second one.

anonymous · Answer

Y =0.42x + 4.49?

anonymous · Answer

I mean 4.41

mertsj · Answer

Wow.  That was fast.  I haven't done it yet.  Hang on.

mertsj · Answer

Yes.  That is correct.  Very good.

anonymous · Answer

Yay!! (:

mertsj · Answer

Oh.  wait.  hang on.  The y intercept is 1.89

mertsj · Answer

(0,1.89) tells us that the line crosses the y axis at 1.89
So the equation should  be y = .42x+1.89

anonymous · Answer

:/ flutter