Inclined asymptote can be found by calculating the limit of sqrt(x + 3) + 1/(x^2), divided by x at x->+oo and x ->-oo
$$\lim_{x \to -\infty}\left(\frac{\sqrt{x + 3} + \frac{1}{x^{2}}}{x}\right) = 0$$
Let's take the limitso,
inclined coincides with the horizontal asymptote on the right
$$\lim_{x \to \infty}\left(\frac{\sqrt{x + 3} + \frac{1}{x^{2}}}{x}\right) = 0$$
Let's take the limitso,
inclined coincides with the horizontal asymptote on the left