\textbf{134-} Two vectors $\mathbf{a} = (1,-2,3)$ and $\mathbf{b} = (2,1,-1)$ are given. The volume of the parallelepiped built on vectors $\mathbf{a}$, $\mathbf{b}$, and $\mathbf{a} \times \mathbf{b}$ is:
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(1) $54$ \hfill (2) $72$ \hfill (3) $75$ \hfill (4) $80$
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