But it doesn't explain it. It is a graph of the equation. But that doesn't explain the equation. That's why I gave the parabola example.
Showing a graphical form of the equation is still only the question but in another format. That's what makes it circular. If you ask why something is Y = X^2 and I only show you a graph of Y = X^2, that's not answer. It's the question in a graphical format.