Answer
$\dfrac{9}{\sqrt {18}}=\dfrac{9}{3 \sqrt 2}$
Work Step by Step
The formula to calculate the distance for two vectors is given by:
$d=\dfrac{|u \cdot v|}{|v|}$
Thus, we have $u \cdot v=-2(-4)+0(1)+1(1)=9$
and $|u \times v|=|9|=9$
Now, $d=\dfrac{|u \cdot v|}{|v|}=\dfrac{9}{ \sqrt {(-4)^2+(1)^2+(1)^2}}=\dfrac{9}{\sqrt {18}}=\dfrac{9}{3 \sqrt 2}$
