Respuesta :

Answer:

3 + 12a

Step-by-step explanation:

3 + 3a + 9a

combine like terms and you have the answer

3 + 12a

Answer:

12a+3

Step-by-step explanation:

Step 1: Combine like factors so 3a and 9a

Step 2: Rewrite the expression 3+12a because 3a+9a= 12a