So this one is a little tricky because in order to solve you need to combine like terms. The only problem is that two fractions don't have the same denominator.
This is what you do.
2/3 - 1/9
= (2*9) - (1*3) / 3*9
= 18 - 3 / 27
= 15/ 27
Simplify.
5/9 + y = 7/9
Now since you need to isolate the variable you have to subtract 5/9 from both sides. Since the denominator is the same you can just subtract the numerator.
So y = 2/9
I hope this helps love! :)