Bài giải:

$\frac{392-x}{32}+\frac{390-x}{34}+\frac{388-x}{36}+\frac{386-x}{38}+\frac{384-x}{40}=-5$

$\Leftrightarrow \left( \frac{392-x}{32}+1 \right)+\left( \frac{390-x}{34}+1 \right)+\left( \frac{388-x}{36}+1 \right)+\left( \frac{386-x}{38}+1 \right)+\left( \frac{384-x}{40}+1 \right)$ = 0

$\Leftrightarrow \frac{424-x}{32}+\frac{424-x}{34}+\frac{424-x}{36}+\frac{424-x}{38}+\frac{424-x}{40}=0$

$\Leftrightarrow (424-x)\left( \frac{1}{32}+\frac{1}{34}+\frac{1}{36}+\frac{1}{38}+\frac{1}{40} \right)=0$

Mà $\frac{1}{32}+\frac{1}{34}+\frac{1}{36}+\frac{1}{38}+\frac{1}{40}\ne 0$ nên 424 – x = 0

$\Leftrightarrow $ x = 424

Vậy nghiệm của phương trình là: x = 424