Another function problem...

Suppose I have the function f(x)=x^2-1 how would I find the intercepts?

The vertex is easy to find by completing the square. y=a(x-h)^2+k where a= h=0 and k=-1 giving the location of the vertex at (0,-1) Could someone explain how I get them? I keep getting the wrong answer--

Bam bah Lam--