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The vectors $\begin{equation*} \mathbf{v}=\langle 2,3,-1\rangle\qquad\hbox{and}\qquad\mathbf{w}=\langle 4,6,-2\rangle \end{equation*}$ are parallel, since $\mathbf{v}=\dfrac{1}{2}\mathbf{w}$ . In this case, $\mathbf{v}$ and $\mathbf{w}$ have the same direction.
The vectors $\begin{equation*} \mathbf{v}=\left\langle 1,2,3\right\rangle\qquad \hbox{and}\qquad\mathbf{w}=\langle -3,-6,-9\rangle \end{equation*}$ are parallel, since $\mathbf{w}=-3\,\mathbf{v}$ . In this case, $\mathbf{v}$ and $\mathbf{w}$ have opposite directions.