54) \(\frac3{2x-2y}+\frac5{3x-3y}\)

\(\frac3{2(x-y)}+\frac5{3(x-y)}=\frac{9+10}{6(x-y)}=\frac{19}{6(x-y)}\).

Ответ: \(\frac{19}{6(x-y)}\).