The graph is a parabola. The parabola can either be in legs up or legs down orientation. That way you can pick values on either side to see what the graph does on either side of the vertex.
For example two standard form quadratic equations are f x x 2 2x 1 and f x 9x 2 10x -8.
It means we have three equations one for each of the points since we know the points given must satisfy the unknown equation. Y x 2 - 3x 13. F x a x-h2 k. Substitute the first pair of values into the general form of the quadratic equation.