1 . x & gt; A, x>b, a>b, then x>a
2.x<a, x<b, a<b, then X < A.
3.x>a, x<b, a<b, then a < x<b.
4.x>a, x<b, a>b, no solution.
5.x>a, x<b, a=b, then there is no solution. (equal to can't appear here)
That's about it.