CUET Mathematics PYQs

If $e^x + e^y = e^{x+y}$, then $\frac{dy}{dx}$ =

If $\frac{d}{dx}[ax^3 + ax^2 + ax + 1] = 9x^2 + 6x + 3$, then $a$ is equal to

If $y = t - \frac{1}{t}$ and $x = t + \frac{1}{t}$, then $\frac{dy}{dx}$ is equal to