Help with this problem

[Bay Area]

Blackcat was trying to see if I could answer this problem.
http://gyazo.com/80b77c575650864b5c87cdea3c9e3aca
I answered 23x and blackcat got 8x

Then I asked sue.....
http://gyazo.com/35c67fc5a89988f42c3d6fab074afdee
He answered -57x....

Which one of us is correct? I'm pretty sure its 23x.

P.S. Feel free to close the thread once the answer is finalized.... wouldn't want people to boost their post count for no reason at all.

 

[Blue Stealth]

(-2x) + (25x) = 23x