Answer
$a$ and $b$ provide the four intercepts of the graph. For a graph with center $(0,0)$ and of the form $x^2/a^2 + y^2/b^2 =1 $, the intercepts of the graph are $(a,0)$, $(-a,0)$, $(0, -b)$, and $(0,b)$.
Work Step by Step
In Example 2, the values of $a$ and $b$ provide only four points on the graph. The four points given are not intercepts of the graph.
