Answer:
Personally I always do the smallest variable in order to make it easier
Explanation:
in this case i would add 3x to both sides because it's (-3x) smallest out of the two. so then the equation would be 7 = 7x - 9
from there you would add 9 to both sides and get 16 = 7x
then x = 2.29 (it's rounded up from 2.285...)