- #1

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- Homework Statement
- See image

- Relevant Equations
- Basic algebra

The first image is the question and the second is the answer.

My thinking is let's say North is positive, and South is negative. Fixed point O is the starting point. Then the question becomes +(2a-b)-(3a+2b). The answer should be -a-3b. I cannot fathom why the book gives the answer as a+b. Any help would be appreciated. Thank you.