Answer: 2a+c
Step-by-step explanation: You add all variables that are positive then you subtract by negatives or vice versa. Add 3a+6a-7a yes subtract the 7a which gets you 2a. Add 8b+b-9b, you get 9b-9b which is 0 so you don’t need b in the problem anymore. -5a+4c+2c then you get c, because it is 1 c. So your answer is 2a+c. :P Hope this helped.
