1. Add 12c, 7c
2. Add - xyz, 2xyz
3. Add 11x, 6x, - 2x
4. Add - 6n, 4m, - 2n
5. Add 3ab, - 4bc, 2bc
6. Add a, 2b, 2c, - c, - b, 3a
7. Subtract (11x2 + 12y) – (9x2 – 7y)
8. Subtract (17mn - 10ab) - (- 12ab + 8mn)
9. Subtract (4x - 5y + 6z) - (3z + 4y - x)
Originally posted 2016-04-10 08:09:10.