Graph the expense and revenue functions.
a. Determine an appropriate maximum horizontal-axis value.
b. Determine an appropriate maximum vertical-axis value.
c. Sketch the graphs of the expense and revenue functions.

A company is interested in producing and selling a new device called an eyePOD (eyewear personal optical device). The eyePOD is an MP3 and video player built into a pair of sunglasses. The user can listen to music from the small earphones and watch videos projected on the screen behind the glasses.