Answer
$\dfrac{8a^9c^{12}}{b}$
Work Step by Step
RECALL:
(i) $\dfrac{a^m}{a^n} = a^{m-n}, a \ne0$
(ii) $a^{-m} = \dfrac{1}{a^m}, a \ne0$
Divide the coefficients by each other and the variables by each other to obtain:
$=\dfrac{-24}{-3} \cdot a^{3-(-6)}b^{-5-(-4)}c^{5-(-7)}
\\=8 \cdot a^{3+6}b^{-5+4}c^{5+7}
\\=8a^{9}b^{-1}c^{12}$
Use rule (ii) above to obtain:
$=8a^9 \cdot \dfrac{1}{b} \cdot c^{12}
\\=\dfrac{8a^9c^{12}}{b}$
