Answer
$\dfrac{2}{x^7}$
Work Step by Step
RECALL:
(i) $\dfrac{a^m}{a^n} = a^{m-n}, a \ne 0$
(ii) $a^{-m} = \dfrac{1}{a^m}, a\ne0$
Divide the coefficients by each other and the variables by each other to obtain:
$=\dfrac{16}{8} \cdot x^{3-10}
=2 \cdot x^{-7}$
Use rule (ii) above to obtain:
$=2 \cdot \dfrac{1}{x^7}
\\=\dfrac{2}{x^7}$