Answer 1

We have

\[\left[ 2\hat { i} \ 3\hat {j} \ 4 \hat {k} \right]\]

\[ = \left( 2\hat { i} \times 3 \hat {j} \right) \cdot 4 \hat {k} \left( \because \left[ \vec{a} \vec{b} \vec{c} \right] = \left( \vec{a} \times \vec{b} \right) . \vec{c} \right)\]

\[ = 6 \hat {k} \cdot 4 \hat {k} \]

\[ = 24\]