How do you solve letter b using a subtraction equation with one variable that has a solution of 2/3

Let x be the variable. Then, a subtraction equation which involves the variable x and 2/3 as a result could be:
[tex]x-\frac{1}{3}=\frac{1}{3}[/tex]because, x wil be given as
[tex]\begin{gathered} x=\frac{1}{3}+\frac{1}{3} \\ x=\frac{2}{3} \end{gathered}[/tex]