4. Solve the equation: $x+\frac{92}{x}=[x]+\frac{92}{[x]}$. (1992, All-Russian Mathematical Olympiad)
(By decomposing the known equation, we get $x=[x]$ or $\frac{92}{x[x]}=$ 1. Then, set $x=[x]+r$, solve $\frac{92}{x[x]}=1$, and obtain $x=n$, where $n$ is a non-zero integer, or $x=-9.2$.)