1. The problem statement, all variables and given/known data A is a mxn matrix and B is a nxm matrix. AB = Im. a) Prove that there's only one solution to Bx = 0 where x and 0 are coloum vectors. b) Prove that m<=n 2. Relevant equations if A is a mxn n>m then there're infinite solutions to Ax=0 3. The attempt at a solution a) Bx=0 => ABx=A0 => Ix=0 => x=0 so there's only the trivial solution. b) according to the equation above if m>n then there would be an infinite amount of solutions to Bx=0 and not only one. Did I do that right? This was a problem on an exam and it relative to the other questions it looks to easy.