We are given coordinates of the school located at a point (9,-1).
Library is located 5 blocks south and 4 blocks west .
According to coordinate axes, south is downward and west is on left side.
So, we need to move 5 units down of 9.
5 units down of 9 would be 9-5 = 4.
And then 4 blocks west that mean -1 -4 = -5.
Therefore, coordinate of the library is located at the point (4,-5).