Question 206597
1/3 s + 7/9 = 4/3 s
s/3-4s/3=-7/9
-3s/3=-7/9
-s=-7/9 
s=7/9 ans.
Proof:
1/3*7/9+7/9=4/3*7/9
7/27+7/9=28/27
7/27+21/27=28/27
28/27=28/27