Б 15) \(\frac{14m-n}{xy}-\frac{2n-3m}{xy}\)

\(\frac{14m-n}{xy}-\frac{2n-3m}{xy}=\frac{14m-n-2n+3m}{xy}=\frac{17m-3n}{xy}\).

Ответ: \(\frac{17m-3n}{xy}\)