\ANG{
Vereinfache ($m\in\ZZ$, $n\in\NN$): 
\[\text{(a)}\,\,\,
\frac{\D r^{3m + 2}}{\D a^{m + 3}}: \frac{\D r^{2m - 2}}{\D a^{m + 2}}
\qquad
\text{(b)}\,\,\,
(3a-7b)^{2n+1} \cdot (7b-3a)^{2n+1}
\qquad
\text{(c)}\,\,\,
\left[ (-1)^{2n+1} - (-1)^{2n} \right] ^5
\]
}
\LSG{
(a)\quad$r^{m+4}a^{-1}$\qquad 
(b)\quad$-(3a-7b)^{4n+2}$\qquad 
(c)\quad$-32$
}