A woman starts at point A and travels 3.0 km to the west to point B then 6.0 into the north to point C. She then backtracks and travels 2.0km to the south to point D. What is the woman’s total displacement?

Question

A woman starts at point A and travels 3.0 km to the west to point B then 6.0 into the north to point C. She then backtracks and travels 2.0km to the south to point D. What is the woman’s total displacement?
-3.0, 6.0,-2.0
s=SF-SI 
          -3.0,6.0,-2.0-0.0(initial)
Answer= -7 ??? is this correct??