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$$\frac{2 \left(5 - \frac{2 \left(5 x + 1\right)^{2}}{x \left(5 x + 2\right)} + \frac{2 \left(5 x + 1\right)}{x}\right)}{5 x + 2} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = - \frac{2}{5} - \frac{\sqrt{2}}{5}$$
$$x_{2} = - \frac{2}{5} + \frac{\sqrt{2}}{5}$$
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
$$\left[- \frac{2}{5} - \frac{\sqrt{2}}{5}, \infty\right)$$
Convex at the intervals
$$\left(-\infty, - \frac{2}{5} - \frac{\sqrt{2}}{5}\right]$$