Hi Zubair,
Remember that whatever you do to one side of the equation, you have to do to the other side.
The goal is to get X by itself.
So first you need to subtract 2/3 from each side--> 6 - 2/3 + X
Now you have to remember how to subtract fractions. You need the same denominators. So let's change 6 to 18/3. . .
all you've done is multiply 6/1 by 3/3 to get 18/3 . . . it's still 6.
Now, 18/3 - 2/3 = X
16/3 = X
You can change it to a mixed fraction by dividing 16 by 3 and get 5 1/3 = X
Dan