What is the correct answer of this equation 7fg + 2gf?

Posted By John "The variables in this question are also the same, being g and f. It does not matter which way around the variables are written, as long as they are both there. We then add like normal to get 9gf - 9fg is also acceptable."
orry John but you must have the variables in alphabetical order. therefore the correct awnser is incorrect.

9gf

The variables in this question are also the same, being g and f. It does not matter which way around the variables are written, as long as they are both there. We then add like normal to get 9gf - 9fg is also acceptable.