Answer
$$=\frac{3z^3}{x^{7}y^{6}}$$
Work Step by Step
$(-\frac{1}{4}x^{-4}y^{-5}z^{-1})(-12x^{-3}y^{-1}z^{4})$
Recall the product rule: $a^{m}\cdot a^{n} = a^{m+n}$
Thus,
$$(-\frac{1}{4}\cdot -12)(x^{-4-3})(y^{-5-1})(z^{-1+4})$$
$$=3(x^{-7})(y^{-6})(z^{3})$$
Recall the negative exponent rule: $a^{-n} = \frac{1}{a^n}$
Hence,
$$=\frac{3z^3}{x^{7}y^{6}}$$
