Solving for Positive Values: When is y = -3/5x^2 Greater Than Zero?

The function $y = -\frac{3}{5}x^2$ is quadratic with a negative leading coefficient, meaning the parabola opens downward. This implies that the function cannot be greater than zero for any real value of $x$ because it reaches its maximum (zero) at $x = 0$ and decreases as $|x|$ increases.

Therefore, there are no $x$ values for which $f(x) > 0$.

The correct choice reflecting this conclusion is: No x.