Missed class last week, and I'm not sure how to do this problem. I have three more like it, but if I can see the processes step-wise, I can do the others. Thanks.

Let S = (v1, v2, v3, v4, v5) where

v1=(1,1,0,-1)

v2=(0,1,2,1)

v3=(1,0,1,-1)

v4=(1,1,-6,-3)

v5=(-1,-5,1,0)

Find a basis for the subspace W=span S of R^4.

What is dim W?

and also...

Are the vectors bases for R³

{(1, 0, 0) , (0, 2, -1), (3, 4, 1) , (0, 1, 0)}