\[\frac{(3a + 1)^{2}}{24a - 24} + \frac{(a + 3)^{2}}{24 - 24a} =\]
\[= \frac{(3a + 1)^{2}}{24 \cdot (a - 1)} - \frac{(a + 3)^{2}}{24 \cdot (a - 1)} =\]
\[= \frac{(3a + 1)^{2} - (a + 3)^{2}}{24 \cdot (a - 1)} =\]
\[= \frac{(2a - 2)(4a + 4)}{24 \cdot (a - 1)} =\]