Can u help me with this please

Step-by-step explanation:
answer is 9+n. You can check in the photo that I have send
Answer:
=> 9 + n
Step-by-step explanation:
=> 18 + 4n - 9 + 8n - 11n
=> 18 - 9 + 4n + 8n - 11n
=> 9 + 12n - 11n
=> 9 + n
Hence, correct answer is 9 + n.