Note: I don't know LaTeX that well, hence I have done my working in the images. 1. The problem statement, all variables and given/known data Show that the rows of G are a basis for the null space of H (part of this question will be to show the independence explicitly). http://img.skitch.com/20090415-f6gewnam8bq6m971y9s7cam55q.preview.jpg Click for full size - Uploaded with plasq's Skitch 2. Relevant equations Nullspace of H is the vector space of x, in which Hx=0. Basis is set of independent vectors that define this space. 3. The attempt at a solution http://img.skitch.com/20090415-reqmbp49jacrhkme1886t1j5sx.jpg http://img.skitch.com/20090415-gwtu1hpgep9aun89isp16jxhwn.jpg Any help you can provide would be greatly appreciated.