1. The problem statement, all variables and given/known data Ok so the question is: Let A be an nxn matrix where n [tex]\geq[/tex] 2. Show A* = 0 (A* is the adjoint matrix, 0 is the zero matrix) if and only if rank(A)[tex]\leq[/tex] n-2. 2. Relevant equations A*:= ((-1)i+jdet(Aij))ij where Aij is the (i,j) minor of A 3. The attempt at a solution I'm really struggling with answering this. If rank(A) [tex]\leq[/tex] n-2 then A contains at least 2 dependent rows. Does this automatically make A* = 0? If A*=0 then (-1)i+jdet(Aij) = 0 for all i and j. So det(Aij) = 0 for all i and j. Having a zero determinant implies dependence?