Find a basis of the subspace of spanned by the following vectors:

4 3 -7 10

6 14 -20 34

1 -4 3 -7

1 -4 4 -7

i turned it into a matrix and then row reduced it and got this:

1 0 1 0 0 1 -1/2 0 0 0 0 1 0 0 0 0

im just unsure what to do now, please help.