Therefore, fits the shaded portions of the graph.
6 . B
You might think at first glance that what you’re supposed to do is graph the ellipse and
somehow figure out where the ellipse crosses the y-axis. But hold on a second! What does a
point of intersection represent in coordinate geometry?
It represents a pair of numbers that satisfies both equations. The y-axis is the graph of the
equation x = 0, so what you’re looking for is a solution for both the equation
and the equation x = 0. Plug x = 0 into the ellipse equation, and you get
When x is 0, y is either 4 or –4, so the y-intercepts are (0,4) and (0,–4), and the answer is (B).
So, what looked like a coordinate geometry question was really a simultaneous equations
question. Don’t be fooled by disguises!
