Why is the vertex formula of quadratic function p (h, K)]: y = a (X-H) ^ 2 + k How did it come out?

Why is the vertex formula of quadratic function p (h, K)]: y = a (X-H) ^ 2 + k How did it come out?

Generally, junior high school mathematics obtains this result through formula. In senior high school mathematics, this formula can be derived with the help of derivative. For example, ax ^ 2 + BX + C = f (x) (a > 0, b > 0), then its derivative function about X is f "(x) = 2aX + B
If f "(x1) = 0 and if any x > x1, F" (x) > 0 if any x