The graph on the top is a function where it shows the place of the work and how much the person gets paid and that for every x-value there is exactly one y-value.
The graph on the bottom is also about the pay and work but it is a relation since it showed for some x-values, there are two to three y-values on a point.
A relation is a set of ordered pairs (x,y).
A function is a relation for which each element of the domain (x) corresponds to exactly one element of the range (y).
The independent variable is the places of work.
The dependent variable is the amount of pay for work.
Domain - [Happy Teeth, Youthful Teeth, Western Dental, Central View]
Range - [12.67-20.78]