The document compares the graphs of the quadratic functions f(x) = x^2 and f(x) = -x^2. Both functions have a parabola shape that is symmetric around the y-axis. However, f(x) = x^2 opens upward, while f(x) = -x^2 opens downward due to the negative coefficient changing the direction of the opening of the parabola. In general, the properties of quadratic functions with an equation of y = ax^2 are also described.