Hope this answer would be helpful.
BETTT
STEP BY STEP EXPLAINATIKN
Add the numbers, then divide your new number by how many original numbers there are. 7 + 9 = 16, then 16 / 2 = 8, so your mean is 8.
It is the first answer. Notice that if you multiply it out you get 6x + 30, and they have factored out the 6.
Answer:
E = number of Ella's stories
A = number of Anna's stories
E = A + 8
if A = 10, then
E = 10 + 8
E = 18