Answer
$=-\frac{x^{12}}{8}$
Work Step by Step
RECALL:
(i) The products-to-powers rule states that: $(ab)^n=a^nb^n$
(ii) The power rule states that: $(a^m)^n=a^{mn}$
(iii) The negative-exponent rule states that: $a^{-m} = \dfrac{1}{a^m}$ and $\dfrac{1}{a^{-m}} = a^m$
Use the products-to-powers rule to find:
$=(-2)^{-3}(x^{-4})^{-3}$
Use the power rule to find:
$=(-2)^{-3}x^{-4(-3)}
\\=(-2)^{-3}x^{12}$
Use the negative-exponent rule to find:
$=\frac{1}{(-2)^3}\cdot x^{12}
\\=\frac{1}{-8} \cdot x^{12}
\\=-\frac{x^{12}}{8}$