Find a set of vectors whose span is the kernel of the following matrix:

1 1 2 0

2 1 0 -1

0 1 4 1

When I calculate the kernel I get:

2s+t

-4s-t

s

t

To find the set of vectors that span this kernel do I factor out the s and t?

s * [2, -4, 1, 0]^{T }+ t * [1, -1, 0, 1]^{T}

Am I close on this one?