write a linear function that represents the cost y of x ounces. Intercept the slope

We are given two points: (x, y) = (12, 2.5) and (16, 3.5)

 

We can find the slope of this line:

\(\frac{3.5 - 2.5}{16 - 12} = \frac{1}{4} = 0.25\)

 

Now we can find the y-intercept. First, pick a random point:

y = mx + b

2.5 = (0.25)(12) + b

b = -0.5

 

The linear function is y = 0.25x - 0.5.

 

To find the missing y-value, plug in x = 8 to get y = 0.25(8) - 0.5 = 1.5