I assume that it's w that you want to know.
We'd want w to be alone on one side, we need to get rid of the 8 and the minus by multiplying the whole equation by -8:
[tex]- \frac{6}{8} =-(-( \frac{w*8}{8} )[/tex]
which is:
[tex]- \frac{3}{4} ={w}[/tex]
So we know that w is equal to [tex]- \frac{3}{4}[/tex]