13) \(\frac{5x-2y}{a}-\frac{3x+y}{a}=\)

\(\frac{5x-2y}{a}-\frac{3x+y}{a}=\frac{5x-2y-(3x+y)}{a}=\frac{5x-2y-3x-y}{a}=\frac{2x-3y}{a}\).

Ответ: \(\frac{2x-3y}{a}\)