# Math Help - nontrivial solution for a homogeneous system

1. ## nontrivial solution for a homogeneous system

Let $A=B=\begin{bmatrix}{a}&{b}\\{c}&{d}\end{bmatrix}$ Show that the homogeneous sytem Ax=0 has only the trivial solution iff ad-bc≠0

I know it has to do with there not being a column of 0s in A.

2. If $ad-bc \neq 0$ the matrix A invertible and the the system Ax=b is consistent for every choice of the column vector b and the unique solution is given by $A^{-1}B$. In the case of a homogeneous system Ax=0, the vector b is 0 and the system has only the trivial solution $x = A^{-1} \times 0 = 0$.