The location of the hospital has already been found by you in a previous question. It is (-6, -4)
Similarly, the location of the police station has been found in a previous question by you. It is (0, -4)
Notice how, though the y-coordinates of the two points are the same, the x-coordinates change. This means that the distance between the two points is just the difference between the two x-coordinates. To find how many blocks apart the hospital and the police station are, we can do 0 - (-6), to get a distance of 6 blocks