Answer
$4c^4$
Work Step by Step
(i) $a^m \cdot a^n = a^{m+n}$
(ii) $a^{-m} = \dfrac{1}{a^m}, a \ne 0$
Use the rules above to obtain:
$=\dfrac{4}{c^{1+(-5)}}
\\=\dfrac{4}{c^{-4}}
\\=\dfrac{4}{\frac{1}{c^4}}
\\=4 \cdot \dfrac{c^4}{1}
\\=4c^4$
