Chapter 5 - Section 5.7 - Polynomial Equations and Their Applications - Exercise Set - Page 392: 69

$(7,21)$

In Exercise $67$ we found that $7$ players entered the tournament if $21$ games were played. So the point in the graph corresponding to the solution in Exercise $67$ is the point having the $x$-coordinate equal to $7$ (the number of players) and the $y$-coordinate equal to $21$ (the number of games played): $(7,21)$.