6. Show that the four vectors below are linearly dependent.

$$v_1 = \begin{bmatrix} -1 \\ 1 \\ 0 \end{bmatrix}$$; $$v_2 = \begin{bmatrix} 2 \\ 1 \\ 0 \end{bmatrix}$$; $$v_3 = \begin{bmatrix} 0 \\ -6 \\ 2 \\ 0 \end{bmatrix}$$; $$v_4 = \begin{bmatrix} 0 \\ -3 \\ 1 \\ 0 \end{bmatrix}$$.