Graphing Quadratic Equations - Math is Fun The simplest Quadratic Equation is: f (x) = x 2 And its graph is simple too: This is the curve f (x) = x2 It is a parabola. Now let us see what happens when we introduce the "a" value: f (x) = ax2 Larger values of a squash the curve inwards Smaller values of a expand it outwards And negative values of a flip it upside down Play With It