Finding the basis of $\mathbb R^5/W.$ I need help finding out the basis in the following question :

Let $~~W=\big<[1~~2~~1~~0~~1]^t~,[1~~0~~1~~1~~1]^t~,[1~~2~~1~~3~~1]^t\big >~$  be a subspace of $\mathbb R^5$ .  Find a basis of $\mathbb R^5/W.$ 

I can't figure out the basis , kindly help with some hint on how to proceed ...

Row reduction of the matrix:
$$\begin{bmatrix}
1&1&1&x\\
2&0&2&y\\
1&1&1&z\\
0&1&3&t\\
1&1&1&u\end{bmatrix}
\rightsquigarrow
\begin{bmatrix}
1&1&1&x\\
0&1&3&t\\
0&0&6&y-2x+2t\\
0&0&0&z-x\\
0&0&0&u-x
\end{bmatrix}$$
shows $W$ has dimension $3$ and is defined by the equations $\,x=z=u,\,$ hence $\,\mathbf R^5/W\,$ has dimension $2$ and it is enough to find two linearly independent vectors that do not satisfy these equations, e.g.:
$$e_1={}^{\mathrm t}(1,0,0,0,0),\enspace e_2={}^{\mathrm t}(0,0,1,0,0) $$
