Is this set of vectors linearly (in)dependent? I have the following problem:
Are the following vectors linearly independent in $\mathbb{R}^2$?
\begin{bmatrix} -1 \\ 2 \end{bmatrix}\begin{bmatrix} 1 \\ -2 \end{bmatrix}\begin{bmatrix} 2 \\ -4 \end{bmatrix}
when I solve this using $c_1 v_1+c_2 v_2+ c_3 v_3=0$ 
I get an underdetermined system, can anyone help me to understand what this means for the linear independence?
Thanks in advance :)

$$0v_1+2v_2-v_3=0$$
In general, you can never have more than $k$ linearly independent vectors in a $k$-dimensional vector space
