Let's find the inflection points, we'll need to solve the equation for this
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
the second derivative$$- (\frac{2 \left(x + 5\right)}{\left(\left(x + 5\right)^{2} + 1\right)^{2}} + \frac{1}{\left(x - 3\right)^{2}}) = 0$$
Solve this equationThe roots of this equation
$$x_{1} = - \frac{11}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2} + \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2}$$
$$x_{2} = - \frac{11}{2} - \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2}$$
Сonvexity and concavity intervals:Let’s find the intervals where the function is convex or concave, for this look at the behaviour of the function at the inflection points:
Concave at the intervals
$$\left[- \frac{11}{2} - \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2}, - \frac{11}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2} + \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2}\right]$$
Convex at the intervals
$$\left(-\infty, - \frac{11}{2} - \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2}\right] \cup \left[- \frac{11}{2} - \frac{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}{2} + \frac{\sqrt{- 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}} - \frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 42 + \frac{318}{\sqrt{\frac{8}{\sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}} + 21 + 2 \sqrt[3]{\frac{65 \sqrt{4289}}{4} + \frac{4257}{4}}}}}}{2}, \infty\right)$$