Answer
$-3 \sqrt 2-2 \sqrt 3$
Work Step by Step
We know these trigonometric values
$\cos \dfrac{3\pi}{4} =\dfrac{-\sqrt 2}{2}$ and $\tan \dfrac{-\pi}{3}=-\sqrt 3$
We evaluate the given expression to obtain: $6 \cos ( \dfrac{3\pi}{4}) +2 \tan (\dfrac{-\pi}{3})=6 \times \dfrac{-\sqrt 2}{2} +2 \times (-\sqrt 3)$
or, $=-3 \sqrt 2-2 \sqrt 3$
