Quadratic graph lines are U- or Ո-shaped, which is called a parabola. A linear graph can be drawn using only three points. A quadratic graph is a curve, so more points are plotted to support ...

Now, h = -b/2a. Plug in the values into the formula, and you get: The parabola's axis of symmetry (x = h) is a vertical line passing through the vertex, so as demonstrated above, this is x = 1.