Answer :

One thing is you need to get x on one side and y on the other :) 
8x-1/3y=16
Just like any equation you subtract 8x
8x-1/3y=16
-8x              -8x
-1/3y=16-8x
Now you want y all alone. So you divide. To me I think you divide by -3. But you might want to check and divided by
by -1/3 (just in case)
-1/3y=16-8x
        -3 
y=-5.33(3 is repeating) - 2.6666667x

I really do this help you out! :D