Answer:
B' = (3, -3)
Explanation:
If the coordinate (a,b) is dilated by a factor of k, the resulting coordinate will be ()ka, ka)
Given the coordinate (1, -1). When dilated by a factor of 3, the resulting coordinate will be;
B' = 3B
B' = 3(1, -1)
B' = (3(1), 3(-1))
B' = (3, -3)