Question

What is the sum of 9c+(8+3c)?

Answer 1

9c+(8+3c)      
9c+8+3c     (collect like terms)

9c+3c+8
12c+8

12c+8 is the answer.
im not sure if your teacher also wants the answer to be in simplest form so im going to do that below as well:

12c+8      (4*3=12 and 4*2=8. you can take out a 4 from those 2 numbers)

4(3c+2) (this is the simplest form of 9c+(8+3c))