1. ## spanning sets

Do the columns of
A span R4? I have no idea where to start. If anyone knows how to solve it I would really appreciate some help with this
$
\begin{bmatrix}0 & 0 &1 & 1& 0 \\ -1 & 1 & 0 & -5& 1 \\ 1 & -1 & 0 & 5&1 \\ 2 & -2 & -1 & 9&0\end{bmatrix}
$

2. Guassian elimination would be a good start.