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