Answer:
9a+b
Step-by-step explanation:
3(a+b)+6a-2b
Distribute
3a+3b +6a -2b
Combine like terms
3a+6a+3b-2b
The answer is 9a+b
3a+3b+6a+-2b
(3a+6a)+(3b+-2b)
=9a+b
