how do I find the vertex of y = x^2 - 18? I got -9, -81 but that seems impossible I think I'm missing something

Answer 1

y = x^2 - 18.

To get vertex you try to write the equation in the form y=a(x-h)^2 +k, where vertex is (h,k)
Our equation can be written as
y=1(x-0)^2 +(-18)
Comparing with the formula equation, we see that h=0 and k=-18
So vertex (0,-18)

Answer 2

thank you!