Exactly, the rules state that brackets should be used (if required) and spaces shouldn't.
However, in this case the rules aren't being adhered to so opinions can be formed on the structure of the equation and the answer it totals.
IMO the answer is zero for the reasons I have given. The following equation isn't formatted properly...
5+4 x 4-1
It SHOULD be (5+4)x(4-1), or (5+4)*(4-1) if that's what you prefer... or X lol.
Using common sense if you were presented with 5+4 x 4-1 you would most likely give the answer 27. If you wanted to be pedantic you could point out that the person who wrote it used the wrong syntax and that there should be brackets in it or else it will be taken as 20.
Of course there would be no argument whatsoever if the equation was laid out properly.