Question

whats the difference between a max and min vertex

Answer 1

For a parabola, say, we have the vertex-form\[y=a(x-h)^2+k\]wher the vertex is the point (h, k).

When a>0, the parabola opens upward, and the vertex is a min;
when a<0, the parabola opens downward, and the vertex is a max
(see drawing)