Question 255162
f(x) = x^2 -7 is a parabola.

the max or min of a parabola is always the vertex

rewrite the equation in "parabolic vertex for

That is:
f(x) = a(x-h)²+k
where (h,k) is the vertex
and a determines how wide or narrow the parabola is, and whether it opens up or down
if a is negative it opens down, and you have a max
if a is positive then it opens up and you have a min

In this case the equation in standard form is:

f(x) = 1*(x-0)^2 + (-7)

The vertex then is (0,-7). Since a = 1 is positive the vertex is at a minimum point.