$ [\vec{a}+2 \vec{b}-\vec{c}, \vec{a}-\vec{b}, \vec{a}-\vec{b}-\vec{c}] $

If $2i + 3j$,$i + j + k$,and $\lambda i + 4j + 2k$ taken in an order are coterminous edges of a parallelepiped of volume $2$ cubic units,then the value of $\lambda$ is:

For three vectors $a, b, c$,the value of $[a \times b, b \times c, c \times a]$ is equal to:

If $a=\hat{i}-2 \hat{j}-3 \hat{k}, b=2 \hat{i}+\hat{j}-\hat{k}, c=\hat{i}+3 \hat{j}-2 \hat{k}$,then $[(a \times b) \times(b \times c), (b \times c) \times(c \times a), (c \times a) \times(a \times b)] = $

If three conterminous edges of a parallelepiped are represented by $\vec{a} - \vec{b}$,$\vec{b} - \vec{c}$,and $\vec{c} - \vec{a}$,then its volume is

Let $\vec{a} = \hat{i} + \hat{j} + \hat{k}$,$\vec{b} = \hat{i} - \hat{j} + 2\hat{k}$,and $\vec{c} = x\hat{i} + (x-2)\hat{j} - \hat{k}$. If the vector $\vec{c}$ lies in the plane of $\vec{a}$ and $\vec{b}$,then $x$ equals: