So x? -4≥0,x+m≥0
The solution is x≥2, or x≤ -2 and x ≥-m.
When x≥2, -m≤ 2, that is, m≥ -2.
When x≤ -2, -m≤ -2 and m≥2.
So there is a solution when m≥ -2.
Therefore, there is no solution when m.
We all know that mathematical symbols are of great significance to mathematics. The symbols