I do not understand how to solve this problem:

Let W = {(s+4t,t,s,2s-t)| s,t are elements are reals}. Where W is a subspace of R^4.

Find the basis for W.

I understand that a basis means that W spans R^4 and is linearly independent. But I fail to understand how to complete this problem. I think I am missing something small.

Any help would be appreciated.