Im stuck on this proof. Let A and B be nxn matricies such that AB is singular. Prove that either A or B is singular. Sooooo, here we go. Let M = AB where is M is the given singular matrix. Becuase M is singular then Mx=0 has an infinite amount of solutions. Let J be one of the non zero solutions Mj=0 ABj=0 this is where I get stuck. If knew that B was singular I think I could prove M is singular but Im having trouble from this way around. Any ideas?