pls help!

$\dfrac{12\sqrt 2 \operatorname{cis}\left(7\pi/6\right)}{3 \sqrt{\operatorname{cis}\left(\pi/4\right)}} = \dfrac{12\sqrt 2 \operatorname{cis}\left(7\pi/6\right)}{3 \operatorname{cis}(\pi/8)} = 4 \sqrt 2 \operatorname{cis}\left(7\pi/6 - \pi/8\right) = 4\sqrt{2} \operatorname{cis} (25\pi/24) = -4\sqrt2 \operatorname{cis}(\pi/24)$