\[\frac{a + 3}{3a - 3} + \frac{2 - a}{5a - 5} =\]
\[= \frac{a + 3^{\backslash 5}}{3 \cdot (a - 1)} + \frac{2 - a^{\backslash 3}}{5 \cdot (a - 1)} =\]
\[= \frac{5a + 15 + 6 - 3a}{15 \cdot (a - 1)} =\]
\[= \frac{2a + 21}{15 \cdot (a - 1)}\]