A+7a will be 8a.
Combine line terms! As you can see, there is 7a and 1a. 7a+1a is 8a.
Or you can also refer it as a+a+a+a+a+a+a+a. Since 'a' is one a, you can just add it to seven a and will get 8a as the answer. Hope this helped!
8a