Answer:
10/9
Explanation:
First, let's convert 1/3 and 7/9 so that the have the same denominator. To do this let's find the least common multiple of 3 and 9.
List the multiples of 3 and 9:
3: 3, 9
9: 9
They have a least common multiple of 9
We need to convert 1/3 so it has a denominator of 9:
1/3*3/3 (we can multiply it by 3/3 because any number over itself is 1) = 3/9
s-3/9=7/9
Add 3/9 to both sides to isolate s
s=10/9
