Answer:
B(-3, -3)
Explanation:
If a point O(x, y) divides line segment XY in the ratio of n:m and the endpoints of the segment are
, the coordinates of O is:

Given that A(6, -6) and C(-6, 2). Pont B is on AC such that:
AB = (3/4)AC
AB/AC = 3/4
Therefore point B divides the line AC in the ratio of 3:1. Let point B be at (x, y), therefore:

Therefore the location of B is at (-3, -3)