I am on the Academic Challenge team for my school, and we were given a basic math problem, in which the answer was $\frac{5x-21}{30x^2}$. I stated this exact answer, although I said "the quantity of 5x minus 21", which they deemed incorrect because the moderator's answer sheet did not have "quantity" on it, rather they just had "5x minus 21". I am now filing an appeal to get this question and the points back. For the appeal, I need references to prove my answer is acceptable. First, am I justified in appealing this, and can anyone point me to a theorem or a reputable website I can use as a source?
Edit: I said "quantity" to ensure they didn't believe I was saying the answer was $5x$ - $\frac{21}{30x^2}$