From the graph the vertex of the parabola is at (2, 0),

The parabola of the vertex is (h, k) = (2, 0), h = 2, k = 0.

The point on the graph of the parabola (x, y) = (1, 4), x = 1 and y = 4.

(Apply vertex form of the parabola equation: )

Now we can find a value.

(Substitute 2 for h, 0 for k, 1 for x  and 4 for y)

(Substitute 1 for a, 2 for h, 0 for k in the formula)

The vertex form of the parabola equation is .