To find the intersection of A and B figure who has the bigger lower bounds and smaller upper bounds out of A and B.
The lower bound of A is -4 while the lower bound of B is (but not including) 1. So the lower bound will be (1.
The upper bound of A is 4 while the upper bound of B is 7. So the resulting upper bound will be 4].
Put these together and get (1,4].
Hope this helps :)
