1. The problem is to understand the notation for solution sets using intervals and unions. 2. The notation $s=]-\infty,-value]\cup[-value,value]\cup[value,\infty[$ represents the union of three intervals: - $]-\infty,-value]$: all numbers less than or equal to $-value$. - $[-value,value]$: all numbers between $-value$ and $value$, including both endpoints. - $[value,\infty[$: all numbers greater than or equal to $value$. 3. The symbol $\cup$ means union, which combines all these intervals into one set. 4. This notation is used to express solutions that cover all real numbers except possibly the open interval $(-value,value)$ if the middle interval is different. 5. Note that $]-\infty$ and $\infty[$ are alternative notations for $(-\infty$ and $\infty)$, meaning the intervals extend indefinitely. 6. In summary, this solution set includes all numbers less than or equal to $-value$, all numbers between $-value$ and $value$, and all numbers greater than or equal to $value$. This is a way to write combined intervals using unions to express complex solution sets.