ANSWER
{x|x<0} and {x|x>0}
EXPLANATION
If the two inequalities have an intersection,then it has a solution.
If the two inequalities have no intersection, then there is no solution.
The inequality {x|x<0} and {x|x>0} has no intersection, there is no solution.
The inequalities
{x|x≤0} and {x|x≥0},
{x|x≤0} or {x|x≥0}
both have intersection, therefore have solutions.
