At a peanut butter factory, the daily production cost, c, for j jars of peanut butter is modeled by the graph below. what are the domain and range of the function c(j)?

1) The graph

The corresponding graph shows a growing curve, its shape is kind of the right half of a parabola that opens upward and starts at the point (0, 2500).

The vertical axis corresponds to C(j), it contains divisions of 2500 units, and are marked 2500, 5000, 7500, 10000, 12500, 15000 and 17500.    

The horizontal axis corresponds to j, and the marks are 75, 150, 225, 300, 375, and 450.

2) Domain

Domain is the set of possible values for the independent variable, which is placed on the horizontal axis. This is the possible values of j.

They are all the positive numbers and zero, the the domain is:

All real numbers, j, such that j ≥ 0

3) Range

Range is the set of possible images (dependent variable); this is the possible values of C(j).

As you can see on the graph C(j) ≥ 2500

Then, the range is [2500, ∞).