1. The problem statement, all variables and given/known data Supposedly the process to solve Ax=0 is to solve Transpose(R).Ry=z (where z is a random vector) and then x=y/(norm-2 of y). 2. Relevant equations 3. The attempt at a solution Ay=b for some random vector b Transpose(A).Ay= Transpose(A).b Transpose(QR).QRy=Transpose(A).b Transpose(R).Transpose(Q).QRy = z where z is Transpose(A).b Transpose(R).Ry=z since Q is orthogonal Then x (the solution to the homogeneous system) is y/(norm-2 y)? But why?