dreid dreid 24-09-2020 Mathematics contestada WILL GIVE BRAINLIEST!! 1. -4a + 7a 2. -9a + 9a 3. -9a - 9a 4. -a + 3a 5. 6a - a 6. 2a+ 3b + c - 10 - 2a - 5b -8c - 2