Hello everyone.

The matrix is

1 1 -1 2

2 2 -3 1

-1 -1 0 5

I calculated the null space of the matrix as

$\displaystyle Span((-1,1,0,0)^T,(-5,0,-3,1)^T)$

Yet the answer is supposedly

$\displaystyle (-1,1,0,0)^T, Span(-5,0,-3,1)^T$

Why can't I express the first as part of the linear combination (i.e. as part of the span)?