The general quadratic equation is

y = ax^2 + bx + c

You are given

y = x^2 - 1

So, the values for "a", "b" and "c" are:

a = 1

b = 0

c = -1

The vertex is calculated by first finding "x" from the formula "x=-b/2a" and then plugging into the equation "y = x^2 - 1" to find "y".

So,

x = -0/2*1

x = 0

y = 0^2 - 1

y = -1

Thus, the vertex is (0, -1).

You can also read the vertex from the graph