Chapter 13 - Section 13.2 - The Ellipse and the Hyperbola - Exercise Set - Page 940: 42

It's a hyperbola

Writing in standard form $\frac{y^2}{4^2}−\frac{x^2} {4^2}=1$ Intercepts : $x=0$, $y^2=16$, $(0;4)$, $(0;-4)$ Asymptotes: $y=+/−(\frac{b}{a})x,$ $y=x$ and $y=−x$ The graph is as below and the $y-intercepts$ are shown