Beginning Algebra With Applications, Chapter 5, 5.5, Section 5.5, Problem 8

The table below shows the birth rate of various countries, in births per thousand, and life expectancy, in years. Write a relation where the first coordinate is the birth rate and the second coordinate is the life expectancy. Is the relation a function?

$\begin{array}{|c|c|c|}
\hline\\
\textit{Country} & \textit{Birth Rate} & \textit{Life Expectancy} \\
\hline\\
\text{Belgium} & 10.48 & 78.6 \\
\hline\\
\text{Brazil} & 16.8 & 71.7 \\
\hline\\
\text{Martinique} & 14.14 & 79.0 \\
\hline\\
\text{Mexico} & 21.0 & 75.2 \\
\hline\\
\text{Sweden} & 10.36 & 80.4 \\
\hline\\
\text{United States} & 14.14 & 77.7 \\
\hline
\end{array} $

The table can be written as the relation

$\{ (10.48,78.6), (16.8, 71.7), (14.14,79.0), (21.0,75.2), (10.36,80.4), (14.14,77.7) \}$

Where the first coordinate is the birth rate and the second coordinate is the life expectancy. So the relation is not a function because the ordered pairs $(14.14, 79.0)$ and $(14.14,77.7)$ have the same first coordinate and different second coordinates.