Answer
$$\| v \| = \sqrt{6}.$$
$$\frac{1}{\| v \|}v=\frac{1}{\sqrt{6}}(-1,1,2)$$
Work Step by Step
Let $ v=(-1,1,2)$, then we have
$$\| v \| =\sqrt{\langle v, v\rangle}=\sqrt{v_1^2+v_2^2+v_3^2 }=\sqrt{6}.$$
The unit vector in direction of $v$ is given by
$$\frac{1}{\| v \|}v=\frac{1}{\sqrt{6}}(-1,1,2)$$