5. Solve the inequality $\frac{1-0.4 x^{2}}{5-x} \geq \frac{2 x}{5}$.
Solution: $\frac{1-0.4 x^{2}}{5-x} \geq \frac{2 x}{5}, \frac{1-\frac{2}{5} x^{2}}{5-x}-\frac{2 x}{5} \geq 0$,

$\frac{5-2 x^{2}-2 x(5-x)}{5(5-x)} \geq 0, \frac{5-10 x}{5(5-x)} \geq 0$ ;

![](https://cdn.mathpix.com/cropped/2024_05_06_8eeeb8d6ace591217257g-04.jpg?height=209&width=554&top_left_y=1923&top_left_x=1411)

Answer: $\left(-\infty ; \frac{1}{2}\right] \cup(5 ;+\infty)$.