4. Determine the number of different values of $a$ for which the equation

$$
\left(3-a^{2}\right) x^{2}-3 a x-1=0
$$

has a unique solution
Answer: 2. (C)

Options.

![](https://cdn.mathpix.com/cropped/2024_05_06_931339780e33dfccbc0eg-3.jpg?height=76&width=639&top_left_y=2075&top_left_x=760)