This is an inequality.
This is what the statement should look like: [tex]57 > x - 8[/tex]
Now, you can actually "properly" reverse these meaning the equality sign changes too. So basically you can mirror them.
The "mirrored" inequality expression would look like this: [tex]x - 8 < 57[/tex]
Now just like normal algebra, you can transpose these terms from 1 side to another and so, -8 would transpose to the right hand side and the operation would be the inverse or in this case, addition. The expression would look something like this: [tex]x < 57 + 8[/tex]
Add them up and you get: [tex]x < 65[/tex] :D