Answer
Vertex: $(0, -4)$
Opens upward
x-intercept:-2, 2
y-intercept: -4
Work Step by Step
$f(x)=x^2-4$
$f(x)=(x-2)(x+2)$
$a=1$, $b=0$, $c=-4$
Vertex: $x=-b/2a$
$x=-0/2*1$
$x=0$
$x=0$
$f(x)=x^2-4$
$f(0)=0^2-4$
$f(0)=0-4$
$f(0)=-4$
Vertex: $(0, -4)$
Opens upward
$y=0$
$f(x)=(x-2)(x+2)$
$0=(x-2)(x+2)$
$0=x-2$
$0+2=x-2+2$
$2=x$
$0=x+2$
$0-2=x+2-2$
$-2=x$
$x=0$
$f(x)=x^2-4$
$f(0)=0^2-4$
$f(0)=0-4$
$f(0)=-4$
x-intercept:-2, 2
y-intercept: -4